well, my own personal opinion is dont let her go without getting both problems taken care of. I never go out out on a road trip of any distance without making sure my car is all set to go and all of the maintenance is done on it. Then again, there are people who drive total shitboxes that are falling apart across the country and back without problems.
if anything, id at least get the steering issue resolved…with the cooling system, the worst that can happen is the car overheats or something. if the steering system fails, well then you’re compromising the safety of the driver and others on the road.