I go camping with my small dogs all the time. I take them with me on hikes. The only trail I've ever not been able to take them was the Pacific Crest Trail.
I think the dog for you is an Italian Greyhound ;)
They are 25 mph couch potatoes. The negative for camping is that most people find them unreliable off lead. I let mine off lead all the time - but I also work her recall every day without fail.
Second negative for your lifestyle is that they "break easily". Mine does amazing athletic feats and has never broken. But, I was holding another IG and dropped him on a bed - and his leg broke! But, I built up Tari's bones/muscles with walks from a young age.
One advantage/disadvantages for you is that they are litter box/potty pad trainable. Tari does her business in the winter on potty pads (IGs have little hair and no fat, so they don't like to go outside in the cold.) This is actually really nice, once you get over the icky thought of a dog pooping in your house - I can take her to hotels and camping, or leave her locked in a room if I have guests with a potty pad down. Don't misunderstand me, I spoil my dogs, I don't leave her locked up! and, this is the same as you'd have with a cat, rabbit, etc.
I would guess that there are other "toy" dogs that might fit what you want (a Yorkie? I have a friend with a Boston Terrier that is a little dynamo). Please avoid "teacup" dogs.
I don't think there is any pet you could just leave in a tent, but there are some little dogs that you can take with you and can sleep in a tent just fine. I have Tari (Italian Greyhound - 12 lbs), Murphy (20lb mutt, who Tari can stand over), Finn (22 lb Mutt). I take them all many places with me.

