Trying to set some time for either but is there a big difference in the two or are they both the same?
It's the same travelling show. So the basic set up is the same. You've got a floor with vendors. Lodges selling trips, fly shops selling gear, all the equipment makers hyping their latest stuff, organizations like TU trying to sign you up, fly tiers ringing the place doing little demo's and selling flies. There are casting pools where you can take any rod you want and play around with it, and at certain times there are scheduled casting demo's by the pro's. In separate rooms there are presentations about techniques, places, etc. You can also take casting classes with experts on a paying basis.
Somerset is MUCH bigger. Many more vendors, much better deals and show specials, many more tiers, etc. It's one of the biggest shows in the country, been there for many years and is well established. And there is a fair bit of PA stuff there, as it's right next door in NJ and a lot of those fishermen travel to PA, NY, etc. Many PA shops will be represented, too.
Lancaster is much smaller. It's only the 3rd year of having a PA show, and 2nd year in Lancaster I think. Vendors sign up per show, so it's still gaining it's footing. But the presentations and the like will be more geared towards PA.
I went to Lancaster last year, and it was cool and all, but nowhere near the size of Somerset. But it was closer and easier to get to, and less crowded.