OMG, no I don't think you'll be ok to drive your truck
read more and you'll find nearly every vehicle involved in a major accident in your town
has a voltmeter 
didn't you start this thread by saying the alternator was bad? how can you drive it?
call a tow operator and have the truck taken to an auto electric shop to be repaired, tell them you want a high output alternator, a volt gauge and
brand new wiring harness
