Not to be pedantic (well, ok maybe) but the reg says a minimum of three landings, you could do more as long as one is the the required 250 miles away. Also, you're going to have to land and very few trainers have the range to to go 500 miles without refueling so I'd say at least one landing won't be a touch and go. At that point the Feds will care less if you're on the ground 30 minutes or 30 hours.