Thanks, those are all good tips!
A few other things that we did:
1. My folks picked up five bicycles of assorted sizes (toddler to adult) at the local Goodwill store for $7 each. The kids used them all the time.
2. Every night after supper I herded the kids down to the local playground to give the other adults some kid-free time (plus it got me out of washing dishes

)
3. Breakfast and lunch were "on your own" affairs but supper was a group meal every evening. The kitchen wasn't big enough so we set up three picnic tables in a row outside to eat on...even in drizzle. If needed we had EZ-Up awnings we could have put over the tables but the weather never got that bad.
I tried repeatedly to get my mom to use disposable paper plates but she refused. Lord knows why.
-Blast