So I dont do a lot of woodwork and cant set up a worshop for the rare times that I do. But I do have a couple of closet updates I need to do, and may end up doing a custom shelfs and maybe a murphy bed for my daughters room update. (Turned teen, and the hello kitty themed room needs to be changed).

I can work with small pieces just fine with my 10" chop saw, have some air nailers, drills etc. I dont have a table saw, and dint really have room for one.
Here are the problems:
1. Larger pieces give me problems. Like making straight cut with the circular saw on a piece of ply or larger board.
Do I buy a clamp one straight edge, or a curcular saw sled, or what? Is buying precut pieces from a lumber yard the better choice here?
2. Handling larger pieces. Dont have room for a dedicated table. End up using a plastic picnic table, which is wobbly, and a BD folding stand, which is too small. Do I need to make a collapsible table, which will be a pain to store?
3. Joining. Dont have a system picked out and not sure which one will work for 95% of general joinery. Pocket screw jig, dowel and screw jig, biscuit joiner, routing for finger joints?
4. Finishing and staining. A can of poly is probably a great choice here, or should I brush? Staining always looks bad. Any hints on how to stain well?
5. Glue. White carpenter or the foaming gorilla types?
6. Any other tips you can share on making things easier?

Thank you.