Installing a circuit disconnect switch is not very difficult. A long explanation of doing this is on www.crvownersclub.com
Briefly: buy an "add a fuse" at an auto store. get a 7.5 amp fuse if the fuse size is different than the stock Honda fuse. Buy an on/off switch (see www.crvownersclub.com for a switch that fits in the blank space on the left side of steering wheel), put the parts together and in one hour you got a switch that kills your accessory circuit when towing. If you are all thumbs and don't want to mess with splicing in a switch, etc. You can buy a kit from Roadmaster for about $70. You will still have to mount Roadmasters toggle switch if you buy their kit or let it hang down under your dash. The price of DIY parts is about $18.
You will ask yourself after doing this: Why didn't I do this sooner.