Update: Bought 16 feet of 2x2 from a reclaimed lumber yard near my workspace.

Now I need:

• Fasteners: I'm tempted to use wooden dowel pins but I feel like I should just find the actual bolts that I need. I think I need a bunch of 3/8 inch bolts that are just over 3 inches long (~90mm), plus nuts and washers.
• Saw: I have a backpacking saw but that feels bad. I'll probably need to use a hand saw because of where I'm working.
• Depending on the fastener used, maybe a bit or socket to hook up to my drill.

I don't have a template to use so I think my first project should probably be a jig for drilling holes with a hand drill. Maybe there are already designs for this? Also, I'm way more bothered than I should be about the imperial versus metric thing. 1.5 inches is very close to 4 cm, but it's not the same. In an effort to avoid analysis paralysis I think I'll just go with the 1.5 inches, because it's smaller, but I'm not sure that this is the right thing to do.