It's so lovely to hear that you're planning a trip to come to visit our little island! Driving is such a wonderful way to explore and it sounds like you have quite an adventure ahead of you.
For booking ahead, that does depend just a bit on where you would like to stay. Some hotels or B&Bs might have a bit of waitlist, while others could be more able to accommodate last-second guests. Luckily, I know just the tool to help! We actually have an accommodations finder
right on our website, which lists hotels, B&Bs, historic houses, and more. Feel free to search by location, anywhere you'd like to stay, to find spots nearby.
What I would suggest is reaching out directly to anywhere that catches your interest, to see when they might suggest booking in order to ensure that you have a nice spot to unwind after your adventures.
I do hope this helps and if you need any additional advice, please don't hesitate to let me know.