We only stayed one night at Castlerigg in a motor home as it was a stop off point for watching Tour of Britain the next day.
It's really well signposted and easily accessible.
I would of gladly stayed a lot longer though, the spot given had beautiful view of the lake, but I believe that viewed is shared wherever you park. It also helped that day was a really nice day.
The grounds are really well maintained and had clean and modern facilities.
We didn't eat in the restaurant but it looked a lively environment and the shop was well stocked with everything you need in case you run out.
There was also a really nice public footpath through a stream and woods which leads in to Keswick, takes about 20 minutes to get there but worth it.
We will no doubt visit again, may take the tent next time to mix it up.