I live in the middle so I don't have experience with sales on the coast. But I can tell you in the northern half of the US cycle sales are very much seasonal. Spring and summer selling a motorcycle is easy. Fall and winter motorcycle sales are hard.
California has generally higher cost of living than in most of the US. I would be inclined to believe you could sell it for higher here than on the east coast. I haven't done it though so I don't actually know. It would depend a lot on where, when, and what you are planning to buy.
What kind of bike? Where on the east or west coast?
Are you buying a new bike when you get here? If not how old of an used bike?
Being from Australia you would probably understand that both coasts of the US are big and full of different places.
Off the top of my head I would say that you would have fewer problems on the east coast then the in California. California has very strict emissions regulations and it may be a bit of an issue selling a bike bought out of state. Someone from California would probably know for sure. I live in South Florida here your legal issues would be small and there is a market for used bikes here.
Have a good ride. I recommend the Utah area for some really beautiful mounts and some good mountain biking. If you stop in Moab you will find many bicycle shops that rent bicycles.
If you get to Florida I like the Ocala area and Mount Dora. Kennedy Space Center is also a good place visit. The Saturn V is breath taking to see. It is big.
I am sure many people can give you other suggestions for places to visit. Just remember, like Australia the US is BIG.
P.S. Don't got to Outback Steakhouse. It will just annoy you. Kind of like how I felt when I went to Colorado Bob's American burgers when I was in Ireland, it was the only place open. They asked me if I want curry on my chips, and then asked me if it was like back home.
California is one of the biggest motorcycle consumers in the world. Also by going east to west, you get to experience the country the way the people who settled it did. sort of, but with more fast food stops and stuff. Stay off the interstates!
I'd probably end in California and unload it there. Large population, high cost-of-living, year-round riding weather, and lane-splitting all work in your favor. San Francisco has an especially active motorcycle community.
If you're buying new, most bikes are "50 state" bikes, meaning they'd meet Cali's stricter emissions requirements.
I think you should not take an opinion from anyone who has not ridden across the country. It's just speculation. I have been across 5 times (round trips)
Don't bother to go across the country to the East Coast. Ride up and down the West Coast and as far East as Colorado Utah and New Mexico. Hwy 1 on the West Coast is just about the best road you can find. Return to San Francisco and sell the bike on craigslist.com there and go back home from there. San Francisco is a great city for a tourist as well.
I grew up and rode in the East and moved to the West Coast. Weather, roads, traffic, people and scenery are all better in the West, in my opinion. Unless you love high humidity, congestion, gestapo cops and lousy roads do not go to the east Coast. The Fly-over states' roads are not my cup of tea, even though the folks seem pretty hospitable.
The Blue Ridge Parkway is nice, but in the Summer it is too humid, crowded with cages and cops. Why would you want to ride the twisties at 30 mph as part of bumper to bumper traffic. Skip it.
I am sure that some will quarrel with my opinion, but you asked for MY opinion. You are entitled to yours, even if it is different than mine. Thanks.
If you are a morning person, I would buy on the East coast and ride to the West Coast. This way you would always have the sun on your back and not in your face when you start off in the morning and you will be stopping for the night before sundown anyway.
If you are a late morning person, I would buy on the West coast and ride to the East Coast. This way the sun would be high enough in the sky that it would not be in your face when you start off in the morning and you would always have the sun on your back and not in your face late in the evening as the sun sets.
East or West might be a coin toss in terms of where to sell. As to advice on a route (you didnt ask outright but I sense you want to know anyway), I'd spend a good while in California then head off through Nevada (no speed limit), angling over to Tornado Alley, i.e., Oklahoma and Kansas, so youre there around April or May, presuming you looking for a little excitement. Its big sky country so storms won't sneak up on you if you keep a weather eye out. From there just keep heading East across Tennessee and Virginia until you get to Virginia Beach and the Atlantic Ocean. You'll be able to get a decent price for your bike there with all the squid wannabes in the Navy hanging around there.
I'm not going to argue with orcyclist, since he backs up his opinion with been-there knowledge. I'll simply say that if it's just the riding you're after, I'd listen to him. But if you're into history, the situation he describes is just the reverse - the vast majority of the interesting stuff (first important settlements, Revolution, Civil War) happened in the East.
I do hope you at least spend SOME time in the East, especially the Northeast. You simply can't miss the Niagara Falls region. See Old Fort Niagara at the mouth of the Niagara River where it flows into Lake Ontario - an 18th century French fortification in a beautiful spot. Then head down the road to Goat Island in Niagara Falls, where you can walk right close to the edge of the Falls. Cross the Rainbow Bridge into Canada and enjoy the sightseeing on the Canadian side - a jet-boat ride down the Gorge, the Maid of the Mist to the very foot of the Falls, the Cave of the Winds at the base. Rent a bicycle and pedal up the Niagara Recreational trail back up to Lake Ontario and the town of Niagara-on-the-Lake - if you're in decent shape, the ride up and back will take two or three hours and you'll be pedaling along what Winston Churchill called "the prettiest Sunday drive in the world." If you don't want to pedal it, just ride the accompanying road on your motorcycle. They're parallel. The bicycle trail can be hard to follow through one town section (I forgot the name of the town), but the locals are your fellow Commonwealthers, so they'll be happy to help. Oh, and it's great wine country, so have a taste at a vineyard. If you do decide to bicycle, you can leave your motorcycle parked on the American side, and walk across the bridge to Canada.
Also nice in the Northeast are the mansions of Newport, Rhode Island; the Lake Champlain-Hudson River Valley corridor in New York (more mansions, the French-and-Indian War Fort Ticonderoga, and Bear Mountain State Park, where motorcycle riders from NYC gather on weekends.) You could hit all of this stuff quickly on the way out West.
Try entering in Minnesota, buy a bike, ride to Brownsville, Texas. Sell the bike. (Why is everybody fixated on East to West?) That way you'll see our country with most of the bumpy stuff ironed out. You will appreciate jumping in the Gulf of Mexico once you've ridden across Texas.
Contrary to what some people here said, there are as many things to see in the East, Midwest, and South as there are in the West. I'd go from East to West personally, but I don't think it matters which direction you go. There is plenty to see in every state. It would take a lifetime to see it all. Take your time and enjoy it all. And yes, I've been to practically every state on a motorcycle myself.
Start in the west, take the Southern Route, then come back across using a northern route, sell bike on West coast, larger market, but a lot more smart a$$es over on the left side of the country as you can tell by the responses. Going both ways (no, not that way, directional) you really get to see the country really looks like.