Yeah mileage really has nothing to do with reliability on a road trip. If you have maintained it according to the owners manual and take care of issues when they arise instead of pushing things off till it becomes a more serious problem you’ll more than likely be fine. Ive mentioned in another thread that both my rigs have 200k+ miles and really wouldnt hesitate to leave tomorrow for a cross country trip. Im religious with maintenance and repairs and trust my vehicle over most any others including rentals. New doesn’t mean reliable or without issues. Make sure tires are in good shape, proper pressure, brakes in good order, battery in good health, fluids all proper levels and changed according to schedule (yes power steering fluid needs to be replaced, its not a lifetime fluid as many seem to treat it like ). Fresh wipers, Wash your windows etc. its amazing how pleasant a road trip can be with a little vehicle prep. Keep a small hand tool kit with you and some jumper cables or jump pack.
Ive done countless cross country trips and my vehicle is usually the least of my worries because i maintain it constantly and know the current condition of everything so its always ready to go.
So base your decision off of maintenance behavior, general day to day reliability (doesn’t leave you stranded every few weeks, etc). In the end its what you feel most comfortable with.