The first step in selling a collection is to compile a basic inventory list. Nobody will expect you to know the fine points of each item, but do your best to describe what you have and take pictures of everything. You can group similar items together (pins, watches, books, etc.) when you photograph them. It's easier to take a list with you to local stores, and its the only way to work with online sellers. Overall, the value you receive will largely depend on the amount of effort you put into selling what you have. Keep in mind that a dealer is only going to offer you about half of what he expects your items will sell for.
Selling them locally is certainly easiest for you. The ideal place would be a store that sells Disney collectibles of one kind or another, but those are few and far between around the country. They may well only want some of what you have, but at least they would have superior knowledge and the customer base to work with you. Antique shops, comic book and collectibles stores, consignment shops, and second-hand stores will often be interested in them, too. If you have an "I Sold It" store in your area, they can be a good place to take such things, too.
Selling them to online dealers has the advantage of more opportunities and they're obviously more likely to be interested in what you have than a generic antique shop. The downside is the necessity of shipping the items to the buyer in terms of both the costs and effort required. Try "disney art" and "disney collectibles" to find dealers, and then Email them your list and photos.
The last option would be to sell your items on eBay. You may well have some items that dealers don't want, so eBay will let the buyers come to you. You can always experiment with the better quality items by listing them at a modest opening bid, and if they don't sell you can relist them starting at $.99. Low opening bids are often the best way to sell on eBay. Despite the risk, you'll almost always get at least one quick bid from bargain hunters and that can get the ball rolling toward the item's actual value.
I hope this helps. Let me know if you have any other questions. Good luck!
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