1. 30 or 50 amp is your personal preference based on your needs. I have been to a couple of FMCA & GS rally's and even though we also have no problem dry camping, we always take power. Why? Generators! Dry campers are generally in one area therefore the noise and fumes can be a problem especially as close as they park you. Also if you choose to leave your pet, if warm you would want to leave your air on.
Getting your toad out should be no problem.
Some seminars are very popular and could fill up quickly, arrive early. Also you often will find conflicting seminars, our strategy is DW will go to one and me to the other, taking notes.
My advice is camp at the rally. These events can be tiring so a quick nap and cheaper eats at the coach is a plus. Also you might just fine that perfect item you need to buy and have installed on your coach, which most vendors will do on site. Ie, I once made a deal on tires for my MH and the shop came to my sit and change out 6 tires the next day.
In any case enjoy, these are great events.