I'm planning a 2 week road trip in the UK for July starting in England (LHR), going to Scotland, and then ending in Ireland (DUB). I have booked flights already...but when I went to book rental cars it looked like it would be almost $1600 for the 2 weeks ($400/wk + $800 transfer fee) ... plus $300 for the Cairnryan-Larne Ferry.

What would you recommend doing to avoid these fees? There are 4 people travelling including me. I was thinking about just getting a 1 week rental from London to Edinburgh ($440 including a $40 drop fee), Flying to Dublin ($300), and then getting a second 1 week rental Dublin to Dublin ($400). So the cost of the flight and the ferry roughly cancel...with airport bs and car pickup/return you save maybe 2 hours, plus the $800 in fees?