Replacing a water pump in the middle of the road is a pretty big job. It'll require pulling the front engine covers off. I'm not sure if it's possible to do it without removing the fan and accessory belts too. You will definitely need to drain the coolant, either disposing of it properly or replacing with a new mixture. If the fan needs to come off, you should have a set of ratcheting wrenches or one size at least (either 12mm or 14mm). For the rest of the job, it can be done with a 3/8" drive ratchet and sockets (10, 12, and 14mm) with a 6" extension.
Something like this kit from
Tekton would be a good place to start. But, the description of it on the page is not accurate. It does not include 1/4" sockets. You don't really need them.
Also, replacing the starter is a huge job, not to be handled on the roadside. If you are replacing the starter contacts, that is a job that could be done roadside, but there should be some lead-up to the starter failing.
Take a look at some threads where people list the items they carry for roadside repairs or off-road repairs. I'm putting together a list of all that I carry in my build thread, specifically
HERE. I just started it, but I will open all my bags and boxes to show what I think is useful.
Good luck.
*Edit: Oops, I reread your post. I was referring to those jobs on the V6. I see you have the 4-cyl. Either way, the Tekton kit that I linked to is a good start to a basic kit.