I'm on this at the moment too. How do you transport your Kart?
There are certainly benefits to hotel rooms but it depends on your budget and your circumstances really.
I'm going converted van route I think.
All circuits that host national events have shower facilities, and to get myself and my son with the kart as well (and possibly wife and daughter on occasion), to further afield places this makes the most sense. On the occasion that the wife and daughter come I expect to stay in a hotel, but just me and the boy means I can convert the van, (L2 or 3 H1 is probably what I'll go for). This means I can use the van as my daily drive and use my car as PX, which then means I don't have the added expense of keeping an additional vehicle on the road. I had a good conversation with someone who went trailer/hotel to van, then back to trailer (though larger and with occasional bed and heater). Its what works for you as an individual and where your priorities lie, as there are pros and cons for each option.
You can obviously just use the car if it's large enough and stay in a hotel, but you'll only be able to carry one passenger and it'll be left exposed and in view in the back at night so not an option for me personally.
