That would be quite a little surprise for River. Not that he would mind sharing a sleeping bag with her, but because he'd never done so with anyone else before. He'd never taken a girlfriend camping with him. Quite honestly, it never got to that point. Maybe that was a little flag that Alyssa was definitely special.
When she popped back out, he was trying to start the fire, lighting matches and blowing, trying to get a good spark. "Caveman, huh? Do I need to club you and drag you by your hair?" He smiled and turned back to fiddle with the fire, finally getting it to light up. "And there we are!" Of course, he wouldn't really drag Alyssa anywhere by her hair. That would be rude! And not to mention abusive!