SBI is a wonderful choice, then again I have been an SBI member since 2004 so I may be a tad bit bias
. Just do your research, which is a good idea before putting down any amount of money.
The SBI forums are wonderful, just like here on Website Babble, the people are very respectful and always ready and willing to help you out.
You do however have to put in the time and do the work. If you're into camping it could really be a fun site for you to put together. The idea sounds very interesting. There are tons of things you can talk about, not just the camp sites you go to, although that's a great idea but you can tell people how to set up a tent, how to make a fire, how to fish. You could even have a section where your visitors tell the best way to start a fire, set up a tent or catch fish.
You could have a section where you and your visitors talk about the best camping equipment to purchase.
The possibilities are endless. Do some research on it, check out other camping sites and add ideas to yours that theirs lack.
I do understand your mothers hesitation when it comes to the money, no one wants to waste $300, especially when we now live in the time of $4 plus gas. Being an SBI owner however I know that what you get for the money is more then worth it.
I wish you the best of luck in your website building endeavors wether you use SBI or not.