Help Wanted

Help me, wise readers. I need ideas to entertain 6 children ranging from 10 yrs. to 8 mos. (Mostly the 10 & 8 year old- I know what my kids think is fun). We are going to New Mexico this week to watch 2 neices and a nephew for the brother & sister-in-law who were nice enough to babysit for us while we went to England. I think it will be fun, but am a little worried about filling the time so their kids aren't bored. I don't want to go too many places- my husband will be working & the thought of going out with 6 kids alone gives me facial ticks.
Suggestions???
Help me... you are my only hope.