I suspect that plain concrete slabs will be your best bet, as they won't break the bank and are easily reversible if you decide on another approach later on. Any big box store will have them in probably several sizes. My personal favourite is 24x24 as you can lay out a nice-width pathway or small patio with just a few, but they are &*(% heavy so you might prefer 18x18. Anything smaller and I think you'd have stability problems with them though if it's not really mushy, even 12x12 might work. If you're in a zone where it freezes while you have standing water you will get frost heave, but you might just be able to relevel them every year - the alternative is to dig down and put a proper base, which kind of loses you the "fast and cheap" advantage that these slabs offer. If you prefer natural stone to concrete, you can also get cut or hand-hewn natural stone slabs, bluestone or what have you. You're likely best off with a textured surface in case it gets slimy and thus slippery. That's why a wood surface there would not be advisable. KarinL

Make sure you use a stain brush and not a paint roller to apply it. Paint roller doesn't penetrate wood deep enough. That's number one cause of peeling deck stain. It's always better not to paint in direct sunlight, but I am not sure how hot it gets where you live.

Combination of advice. The advice from the paint store fella is how the company advises their products be used. However, the clue is keeping a wet edge. If you let an edge dry, the next application will simply be over a dry area, and that is where the peeling can happen. So, the big IF---IF you can keep a wet edge, you should be fine. IF you cannot, you will probably have problems. There is where Jane's idea has merit. Apply stain early, when keeping a wet edge is easier. That will make the application area larger and you will get done faster. Or, wait for a cloudy, rainless day.

A phony plant in a sun room makes no sense at all and if you are actually planning on using the space invest in some solar shades and since the space gets so much light I would choose another color instead of yellow.The reason you see so much wicker in sun rooms is that the sun ruins fabric and wood very quickly that is why I say solar shades to keep the view but block heat and UV rays.