LOL!
I just got back from a week vacation, and was trying to figure out the same thing (my husband didn't want to take care of the frogs either

This is what I did, and it worked great:
Bought a timer for the light cycle.
Bought a zoo-med hygrotherm (found on amazon) and attached my heat source and reptifogger, this successfully regulated the heat and humidity.
The only two things my husband had to do was make sure the reptifogger had water in the container, and pour some crickets in the viv about twice. And I did remind him so he wouldn't forget. Oh, and of course change out the water bowl every other day.
If getting this set up ready before your trip isn't possible, then your plan sounds ok to me... as far as making sure the plants don't topple over, maybe some floral tape and tape to walls of tub?
Good luck!