I've never been to Hillestad's but I know Louis has been several times and I've heard it is fantastic.
Jim's museum is amazing. For those of you who have visited my little museum, imagine an entire house with two stories instead of one floor, add about 20 times as much historical materials like swords, lances, uniforms, medals, documents and photographs, and imagine a display of about 3 times as many figures (from just about every company imaginable) and dioramas, along with at least 10-12 big ships, and you have some idea.
When Jim retired from his job as a banker, he bought a huge plot in the Pocanos with two houses on it, one for him and his wife, and one for his toys. Jim's museum is open pretty much by appointment only. Just call him, tell him you want to come and he'll set up a convenient time.
Some of the stuff in the museum is available for sale, so you can ask, but don't be shocked if he says no. Maybe one in four times I have asked if something is for sale I got a yes. And if he is willing to sell something you want, don't be shocked if he conditions the sale on you buying a whole set up (for example Hans had to buy the entire matt parade series of Black Watch and Royal Marines to get the Edinburg Castle Facade, and I had to but the entire World of Dickens series to get a diorama of St. Paul's steps Gordon Neilson had made to display the series).
Jim is a good guy, and really knowledgeable, but a bit of a curmudgeon, so if he seems a bit grouchy on occasion, don't take it personally. He is very generous, and has even loaned me books I was interested in reading. However, I have invited him to take the hour and 20 minute or so drive to attend the Symposium each of the last three years, and his response has always been "No. I hate going to New York with all those people around."