Where did Nala come from? Can she stay there while you're out of town?
I did not have a good experience with Rover.com. Don't do it.
Can you find and make friends with another basenji owner in your area where you can take turns pet sitting? Maybe you can find local basenji owners on Meetup or Facebook?
My heart would break to leave her at a boarding facility or a vet although she'd probably be fine. I like the idea of a pet sitter staying at your home ONLY IF you can really train the pet sitter on several visits before leaving in August (not far away!!!)
