Ditto what Sydnie said.

B&B's are usually very reasonable with the same accommodations standards as many 4 star hotels. I've been pleasantly surprised many times.

Self-catering is another viable alternative, though you'd better start securing these now.

A larger vehicle will be substantially more to rent and the fuel costs.... Also, some car rental firms don't permit taking their vehicles off the mainland. Check 1st, 'cause you'll be uninsured if'n you do.

Good on yall for touring w/o a group. You'll see far more and not be forced to go places you'd prefer to avoid when locked into a scheduled tour.

Slan,
steve