You probably know this but you usually only need touch up paint if you scratched through the clear coat and into the paint. Otherwise, you can reduce the scratch visibility significantly by using a scratch compound like Mcquires Ultimate.
I've also found if the scratch is deep, I can "Mcquires" most of it away, mask the area with tape and use a spray clear coat (spray can from the auto parts store). After it dries I "Mcquires" it again to blend the edges. Takes about a week for the Sun to dull the clear coat like the rest of coach.
I'm not a very good RV driver...