There is no problem.
You use your dads equipment M T W on his accounts
You use your equipment on your accounts T F S.
So you drive 45 minutes to do dads route. Once you get there they are all close.
You have the ability to not only build up both routes but areas in between as well. With good luck and hard work you will have enough business to expand to a two truck route.
Do you and your dad work solo?
Team up and you will knock out both routes in half the current time then solo. Then more time will be open to add more customers.