1.) You will not need a patch panel, unless you are big on Lan Parties, or have a massive farm of servers storing up your massive collection of DVD's, and MP3's. Some houses where I live here in South Orange County, CA (Ladera Ranch) have patch panels. I could be wrong, you may have a patch panel or switch in that house. (your broadband connection and switch, router, wireless access point may all be hooked in this location)
Hook in the router to the wall socket with a regular patch cord. Not a cross over.
2.)Not worth to use a hub, get a switch. If you do use hub from switch, then use a cross over cable. Run the hub off the uplink port on that BEFS41, if you have the newer version of it, run it off of port 1 and use a cross over cable.
3.)You will need another Wireless AP if you decide if you want more wireless connectivity in the house or in your garage. I really don't think you need another wireless access point in your house. With the exception if you have a two or three story house. I am not sure what the limit is for the 54G Linksys, but do contact Linksys for more infor on how many computers you can use for wireless connectivity. I run this set up in my house with both wireless and cat 5. (Secure wireless that is)
4.)Yes, there is a cat 5 cable tester you can pick up at your local electronics, networking store, or at Frys, since you are Arizona. Tempe and Phoenix. You can plug into the jack. More expensive equipment like Fluke, or Sunrise have advanced testing of cables, jacks, and telephone equipment, that can provide you signal analysis. Some have a build in time domain reflector. TDR, how much delay you may have in that cable. Or signal strength on the cable itself.
Or simply you can hook in two machines into at seperate jacks, and ping the machine on the other end, and see what the millisecond delay is. Or ping the BEFSR41 switch. Or use a laptop and alternate to different Cat 5 jacks in the house with a machine at one end, to find which are the best jacks, and which are the worst via ping.
I hope this can help, or that some people in the forums can add. There are many helpful people here in the forums with different backgrounds.
I will list a website that is helpful below.
http://www.practicallynetworked.com/