Here's my opinion on the matter: If someone else is sharing the shelter with you, then please don't hang your hammock inside because thats just rude. Instead hang from a tree nearby. If you're the only one at the shelter though, I say go for it. Happened to me a few times and I just hung right across the shelter inside. Thankfully I did because it started to pour buckets one night. I use a blue tarp to hang over when I'm suspecting inclement weather, and I'll be 100% honest, it has YET to work...I get wet every time. The ground gets wet, my stakes don't hold, the tarp is never long enough, it rains upsidedown and sideways, etc, etc, I always end up wet. So if there is a shelter and it's open with nobody else to share, I'm gonna hang inside of it, especially if there's rain coming.

With that being said, I have hung outside out of respect for someone else in the shelter then just move in once it started it drizzle and slept on the floor.

Regarding being cold, it's summertime so I never bring my sleeping bag so I put pads down and that didnt work, tried a quilt too (waaayyy too heavy) and that didn't work either. So now I just bring my sleeping bag and sleep in that in the hammock and it works great, no problems. I do get hot sometimes though, but I'd much rather be warm and able to take off clothes than be cold and have no more clothes to wear.

I usually drape a big bug net over me as well just because I got tired of waking up with mosquitos in my ears, nose, mouth. I'm sure the Hennesey-style hammocks work great, but frankly I don't have that kind of money (student) so a little improv and I get by just fine. Have fun hanging.

Oh another tidbit of advice, I LOVE to swing in my hammock and I'm like a little baby if it rocks I fall right asleep so once I climb in that hammock, give a little push to start swinging and I'm passed out in minutes. Cheers