Try looking at the big box stores for the spray on texture patch. They come in something like 8oz spray cans. They are around $8 per can and by the sounds of things you'd probably need just 1 can to do all the patches. Of course you will want to experiment/practice to get the right look before you launch into doing the actual repair. I imagine "feathering in" the patch with the existing texture is going to be the biggest difficulty.
I also used a roller to paint my popcorn ceiling. You do end up knocking off any loose pieces, and sometimes it is tough to fill in all the "pores", but I found that walking around with a halogen torch light afterwards would really light up the ceiling and show you where you needed to touch up. Of course it was quite literally a Pain In The Neck
Good luck. I doubt you need to fund someone else's vacation account for a job like you describe.