Most auto parts sell a nylon mechanical oil pressure gauge line set up that has all the fittings you need except the one you'll need at the very end depending on if it's your filter or injection pump. That one you have to come up with separately.
I always push the small tubing though some larger tubing to provide a sheath to protect against cuts, kinks and abrasion. You can cut the ouside tubing into shorter pieces to make pushing it though easier. Just use electrical tape to connect the pieces after pushing the small line though.