Brent - congrats on the fairly new home. How is the basement coming along? When can we expect some updated pictures of the collection if it has made it to see daylight.
Matt, thanks for the comments. At this point, nothing much is happening much to my dismay. We really need to wait through to the spring to check the walls and floors after what turned into a really cold winter. Make sure there's no cracks or leaks or other structural flaws. So to that end, there's really not that much we can do.
With respect to the eventual toy room itself, I need to finish the outer wall that will have the doorway in it. I can do that fairly easily when I get around to picking up some more lumber, something I have been putting off regularly. I can also frame in the closet for the room but we'll probably leave the drywall down for the time being. If we do drywall anything, it would only be the left wall in this picture as it's not butting up against anything structural at the moment.

The 2x4 on the left is actually the wall, the rest of the wall just runs in a straight line behind. I also need to put in the subfloor before drywalling, so that's all probably going to wait until after the spring and the one year warranty is up. (Warranty is actually five years, but the first year it's sort of a no grief warranty, after that we fight)
Other plans for the basement are getting the other walls up in frame form. It shouldn't be too bad, though I'm a little leery about the framing by the stairway, that I've never done before and is more complex than just making right angles and following chalk lines. For framing the remainder of the basement though, here's what I need to do:
Wall 1 (wall to close off my collection room): 7' 0.75" wall with door.
Wall 2 - opposite to coll. room door: 9'0" wall with door (utility room)
Wall 3 - wall along stairs on west side: 15'5" no door, but access panel to read water meter
Wall 4 - wall along stairs on east side, just to close in stairs only about 6'
Wall 5 - wall along back of utility room to 90 angle with wall 3; has door: 13'2"
Wall 6 - outer wall to bathroom in SE corner (outside walls of house form two other walls, wall 5 completes) with door: 8'0"
So basically I can do lots of framing but won't finish the bathroom wall (#6) until we have the shower/sink/toilet/subfloor in there.
Tons to do, but I know as soon as spring comes I have to finish the fence (about 100' left), build a deck and get some landscaping done so we're not living in a mud pit again. That all means my room realistically won't be done until next winter at the earliest. I do think the basement can be framed if we have rainy weekends during the summer. The subfloor and drywall can go up too.
When we get to the room, I'm thinking about putting in some built in shelves along that left wall also, from the closet to the outer wall. It's going to make the room fairly narrow probably, but should be more efficient and cheaper than buying shelving later. I saw a neat display idea at a jewelry store a while ago that looked good and had pot lights at the top. The goal is to have the room be a functional bedroom, should the use pattern change (like say a teenage daughter) but it should be mine for 10 or so years.