Re: power tool voltage for cruising: 12V or 18.5V or 110V AC?
I haven't had a working battery for my 12 volt drill in years. I run it directly off my 12 volt system, something which wouldn't be an option with an 18 volt drill. Go for the 12 volt and make up a cord for it. I use mine all the time.
When it is new, it's also a good idea to get rid of that screwball keyless chuck for a proper keyed chuck. Mine is frozen on , so can't be changed. Many use a standard left hand 3/8th inch fine thread. Wish I had changed mine , while it was new.