We FTd for 7 yrs.....dog was a Border Collie/Lab mix (78#) and was 4 yrs old when we hit the road
If we couldn't take her with us (going to see an attraction or such) she would stay 'Home' (our 5th wheel) and sleep/relax/lick her bottom or whatever a dog does at home while their people are gone ----just like she did prior to us traveling
Otherwise she went with us in the truck.....if that involved some shopping etc she laid down in her seat and relaxed/people watched etc. just like she did prior to our travels.
As she aged we shortened our time she was left at 'home' alone.....our activities were done with her needs in mind, just like we did when we came off the road and back into a S&B .