I've got the same set up as you, similar mileage. It's stiff especially when cold, but if I'm at a very slow crawl I can downshift to first (parking lots, etc.) Otherwise I can downshift at about 5mph. I don't like to shift before then because it really is senseless with my driving environment/habits. IF I needed to suddenly accelerate, I'd be closer to redlining it and I'd rather lug it in second instead. We haven't had occasion in the mountains to resort to first gear yet unless we get behind someone who is too timid to drive with chains on above 5mph. I also find some stiffness trying to get her in reverse when parked unless I clutch in, brake off, and let her roll forward/backward a tad, then she'll easily reverse. She can be quirky but has never failed us. :)
BTW I'm guilty of starting her off in second gear a lot *g*. My dad's old 77 RamCharger was a conversion from tree shift to floor shift and the gear pattern for shifting was opposite. I was raised with that configuration- first gear was down on the pattern, not up (thankfully I don't try to upshift to reverse!)