Even in a C172 I'd try to get high. 6 or 8000, depending on wind. If at MTOW in summer then climbs even to the lower levels can be slow, extending the period not in cruise conditions. I just found it easier to not to include a 'built in' nav. error at the start. Especially on longer legs over the desert.
Certainly around the East Coast it's not really practical. Airspace limiting the climbs & routing, for example.