I've been making a few 2.5D Dungeon tiles over the last few evenings. Below is an example of the size of dungeon that may be created using one set of pre-printed 2.5D Dungeon Sheets.
I've not made any of the columns, altars, tables or other items yet. If you'd like to try making your own set. You can get PDF of the textures here:
Or you can buy pre-printed sheets here: