Possible lifter issue in suburban? How far can I drive it?

Hello, Never heard of Hallsville, but the zip code is east Texas, right? Well, in east Texas during march, I would not expect the lowest temperature to be anywhere near 90-100 degrees, so 20/50 is much too thick of an oil according to your owners manual. A better move would be changing to synthetic oil of the appropriate weight. It is impossible to guess a breakdown, but lifter ticks are not too worrisome. What is worrisome, however, is that the issue is undiagnosed. That means this could be a lifter, or a number of other things. Lifters are typical, yes, but why chance it? Have it inspected and serviced for long road trips, that is something I recommend to family even when they have newer cars/trucks. If you are having doubts about the longevity of the vehicle, that advice should go doubly for you.