Motorcycle Repair: 1970 Electraglide repair, volt meter, foot brake

Question
I have a 1970 Electra Glide.  Here are the problems I am having:

The battery is not charging properly.  I upgraded the electrical system in 2003 with a 32 amp charge kit, an electronic ignition, and a  Dyna Super coil.  In the next two riding seasons, I've replaced the battery twice, and the one currently in it is now not holding a charge.  What should I have checked to determine why it's doing this?  

Also, I'm not getting sufficient stopping power. The front brake is fine, but the rear is not.  I had the angle of my foot brake petal changed.  Might that be the problem, or is it more likely to simply need new brakes?  What does that entale, a new drum, and what else?

Last, I'm losing oil, but not from under the bike as you might expect.  Instead, I see oil leaking from around the rockerboxes.  I have no idea what that means I might need to have done to correct.

I'd like to know how much each item above might cost me, parts and labor.  I like the bike but I'm at the point where I'm wondering if I need to completely overhaul it, or simply let it go and get something newer.  Speaking of  “complete overhauls”, what all should that include?

In your explanations, please feel free to break it down as though you are talking to someone who knows very little about mechanics, because you are.  

Thank you in advance.


Answer
For the charging problem. First you need to check the battery and make sure you have a good one. next, start the bike and with a volt meter test at the battery and see what the voltage is. You should be running somewhere around 13.5 volts. If not, test the stator. You will need an OHM meter and a AC volt meter. Unplug the regulator from the stator. At the stator pins check for ground with the OHMs meter. If it tests ok, then start the bike and check the stator with the AC volt meter. You should be showing around 50 to 60 volts. If it does not pass the tests then the stator is bad. If it does pass then the regulator is bad.
Rear brake. You will need to remove the drum and inspect the brake to see what the problem is. The shoes might be worn out.
On the leak. Sounds like your rocker boxes are leaking. The heads would have to be removed to replace the rocker cover gaskets. As to cost. Its hard for me to say what the cost would be. Not knowing what parts are bad. Also, labor rates are different all over the country. I only know what I charge in rates.A complete overhaul would be removing the motor and rebuilding it. The bearing as well as gaskets would be replaced. All other parts would be inspected and miced for tolerence.
Good luck and happy riding
Mike