usually i didn't left my cats long... only one/two/three nights... leave them
at home

the day before :
1. clean up their litterboxes - fill with new litter
2. ensure fresh water - fill up all the waterbowls
3. feed them canned food
4. prepare their room
5. cuddle them a lot

right before i left
1. ensure i left them a lot of kibbles
2. hug them
3. put them in their room

i like to left them in their own surroundings rather than leaving at boarding places or with other cat lovers...

anyway, my cats quite happy with the arrangement and greet me enthusiastically when i come back