When my family and I were living in a temporary apartment for a couple of months, this is what I did:

i got two twin sized air mattresses that are tall ( so super thick ones, not the kind where you are on the floor in the middle of the night). they were cheap. And then I pushed them together and got one of those cushy egg crate things to put on top, then a mattress pad and then sheets. IT looked like a big bed. And I swear to God, it was so comfortable. If my husband rolled over then it didn't affect me because I was on a different air mattress under the egg crate and mattress pad. I had my third child while living in this horrible apartment, but the "bed" was honestly so comfortable.

http://www.target.com/p/coleman-comfortsmart-double-high-airbed-twin/-/A-13192229?ci_src=17588969&ci_sku=13192229&ref=tgt_adv_XS000000&AFID=google_pla_df&CPNG=PLA_Sports%2BShopping&adgroup=SC_Sports_Top+Performers&LID=700000001170770pgs&network=g&device=c&location=1013777&gclid=CKn-ys-rsskCFY-Cfgod100HqQ&gclsrc=aw.ds

I did keep the full bed we already had in our guest room for my DD when she came out of her crib. She played in her room just fine (often on the bed rather than the floor) but mostly played downstairs anyway. Second child got bunkbeds and when guests come #1 goes onto the top bunk (a treat for her!) and guests take the double. Now that DD is older, she's happy to have the bigger bed.

My 6'4" DH and I sleep in a double so it's not a big deal.

I have a house full of guests right now. I do have a guest room with a double bed, but far more guests who need to sleep! I put one niece in my son's room (and I recently upgraded him from a twin to a full partly with having an additional guest room in mind, as I have some special family circumstances going on). Another niece has the guest room, and all of the 'boys' (2 kids, including my son, and 1 adult) are sleeping in the downstairs open family/play room. I have 1 twin mattress that I saved from my son's bed that I put down, and then a queen air mattress. It is tight but it works.

Do you really want your kids to be the kind of people who feel entitled to their own beds when grown up guests are sleeping over?

Anonymous wrote:We have only queen sized beds in our rooms. King is only in the master bedroom. We never have a problem when guests come over because our kids move into our room (with one air mattress) and our guests then have 3 bedrooms with queen beds.

We also have a queen futon in our study.

I love when people answer without reading the question -- OP very likely doesn't have room for queen beds in her bedrooms, plus a queen bed would be a bit much for a 2 year old. In my house, the queen bed literally takes up the ENTIRE guest room. There's not even room for a dresser in there. Fortunately the closet has some shelves.

OP - we will have this problem, too, when the new baby arrives. And while I totally understand why you don't want to fill up your older child's room with a full bed, that's probably what we're going to do (full sized futon, so it's low to the ground, at least). It's how we managed guests when I was a child (as the youngest, I got kicked out of my room first and slept on a foam mattress on the floor in my parents room). We have tiny bedrooms but DD's play area is mostly in our living room anyway, so it's okay.