We had something like this that served us so well for years and year! Our son was a Lego maniac and loved all the other building toys. It started with Brio trains actually - and I got tired of the stuff all over the house even though I loved that he got so involved in building elaborate set-ups. We had a big unfinished basement, so we had a handyman actually build us a table. It's roughly 5x8 (about the size of a big sheet of plywood) and then he put trim around the 4 sides so there's kind of a drop side. He made simple legs out of pine boards (maybe 1 x 6??) and he came up with the idea of making 2 sets. 1 set is about coffee table height (good for younger kids because they can lean into the center of the table) and the 2nd set brings the table up to regular height (30 inches). The hardware is simple and we were able to make the change ourselves.
He painted it green so that would be the "grass" around the train sets, the Lego castles, and everything else. Our son combined things like K'nex and an old set of Constructs that was a hand-me-down from a friend's older son, Micro Machines, Hot Wheels, you name it. The table allows an extended use and much more creative play.
You could have someone build a table, or you could buy an inexpensive 3-5 table at one of the warehouse club stores. Or you could find something cheap at a thrift store and either paint it or try something like sticky Contact paper. The paper will never come off the table well, but you can put something new on top if you want. You could use brown kraft paper (from the office supply store) for the beach (and she can color it with markers if she likes. You could tape the open edge down with more green contact paper or colored duct tape. It's not elegant, but it's changeable. Or, you could cut out some colored paper in the right shapes (blue water, tan sand) and take it to the quick printer to be laminated so it doesn't rip. If the lamination film is thin, have them put it through the machine twice. Then your daughter can move the pieces around at she wishes, and they can be wiped off with a sponge if they get a little yucky.
We also have a coffee-table size table that is excellent - the legs are adjustable from coffee table to desk height to counter height. We got it at the warehouse store but they have them at big hardware stores (Home Depot) and places like target. The adjustable height is great for growing kids, and it can be folded up if you need the space. These are washable tables and can be scrubbed down when they get bad. We use them for outdoor parties and BBQs too.
All the stuff - K'nex, Legos, etc. - were stored in marked bins underneath the table. We also used it for school projects and we kept art supplies (markers, colored pencils and all that) in those plastic drawer units from the discount store. We had the type where the drawers can pull out, so a drawer full of crayons could be plopped right on top of the table, then put away when done.
It made clean-up very easy - just pull the open bin out halfway, and sweep the appropriate toys right into it! Legos in one, K'nex in another, train tracks & trains in a 3rd, and so on. We put a photo or a piece of the original carton on the side of the bin, or a big label once he was a good reader, and so the contents were obvious just by glancing at the bin.
This table saw us through high school (Nerf ping pong for fun and big school projects like science fair stuff) and college (beer pong), and it was great for me cutting out sewing patterns and wrapping holiday gifts. We've had it almost 20 years and it's still sturdy and in great shape - when needed, we throw another coat of paint on it. Best investment we ever made.
