An army supply store would be your best bet.Beyond that, I'd guess a camping supply store - but chances are they don't stock camoflage.
Drywall access doors are small access doors that allow on to access plumbing in the walls. Any plumbing supply store or website should have them available.
There will be solvent for the plastic. -Find out WHAT plastic, then get the solvent. -A 'plastics' store or plumbing store is your best bet.
If you are in need of commercial plumbing supplies immediately, you might check with local "big box" stores such as Home Depot and Lowe's. They will often have the supplies needed and many plumbers who need something in a hurry go there. However, to get the best price, you might need to go to an actual plumbing supply store which often sells wholesale, therefore might not sell to an individual.
Best Plumbing in Houston
There are many sources for plumbing supplies. You can either go to a store for them or look on your computer. You can check out Home Depot, Lowe's, or Menard's.
Your best way of finding that out is to go to a good hardware store and looking. Apart from pipe wrenches most plumbing tools are too hard to describe
You should go to the boat supply store. You will find the best speakers for what you need and with installation on your boat with no compatibility issues.
At a pottery store.
Your best bet for DIY kitchen and home remodeling supplies will probably be your local hardware or home store - they'll have the equipment and tools along with kits and guides in stock. Try a national outlet like Lowe's or Home Depot; you might need to get specialized plumbing supplies at a plumbing supply outlet.
Jerry's Artarama is my favorite art supply store. They have everything you need to be an amazing artist:canvas,paint,pastel,paper,brushes,etc.
Your best bet is going to be a home and garden supply store.