Crickets breed faster but roaches are easier. You will very seldom find dead nymphs in a dubia or orange head colony. And you could go on vacation for 2 weeks and it would only slow down breeding and growth. I use no water with my roaches just fruits and veggies.
Would not worry about UVB for 2 days. As for heat, just keep temps mild. 2 mornings without basking probably won't hurt but you could keep give him a little incandescent lighting in the morning (at the hotel?) Before you leave.
the only helix i saw were 3 adults for $15. I never really looked before. I was looking at the giant African snails. So cool. They are edible so I guess they work for chams. I used to raise some kind of native snails years ago for my plated lizard. Not sure if they are ok for chams either.