I did all by myself while Byron was gone last week. I didn't trust Harper in there any longer during naptime.
I don't know who loves it more, Natalie or Harper. Natalie can now climb into it by herself my using the mattress as leverage but hasn't worked up the nerve to jump out. Harper will sit in there for 15-20 mins after she wakes and play with her book or toy I've left in there.
And course the two of them together could probably stay in there all day, or at least until one got hungry.