Don't know if your on your trip yet, but contact your local rescue.
Sometimes they have people who foster who might be willing to pet sit for a fee. I'd personally offer the same fee your vet wants asking that they let your bun out for runs and what not. 20 a day is a GREAT fee. I pet sat for a friend and she gave me 100 for 2 weeks, which is ok because I was doing it for free
. Make sure you either have them make a contract or you make one. Have it state things like what you would like them to do, when your dropping bun off, when your picking up and any financial information (personally I'd pay half when you drop off and half when you pick up but that's just me).
This is just my 2 cents as a person who has pet sat and recently (possibly) got a pet dumped, though loving the bun don't get me wrong.