We recently came into Durango from the east on Hwy. 160. In our gasser, it was slow going towing the Jeep. We are now in Montrose via 550 - we drove up disconnected to give Squeaky a break. The grades are doable and 550 is in very good shape. The twist and turns get a little tight between Silverton and into Ouray as does the grade angles...still should be no problem. It's just another 'scenic route'.
Hwy 50 from Gunnison to Montrose is fairly tame. Don't miss Black Canyon of the Gunnison NP with your toad(grades are steeper going into the park from 50...road is good as well. Only concern I've heard from other RV'rs is Monarch Pass east of Gunnison is a little steep for some of their co-pilots tastes.
Weather wise...I have no clue. Three days ago, we were Jeep'n on the top half of the Alpine Loop...3pm, we got snowed on, hit with hail and had temps in the low 30's. Lake City is where the DW cried Uncle, so we took 149 north and west on 50. Today we got hit with a very cold wind shear here at the CG. Lasted less than 5 minutes. So, weather is a toss up...year round, so say the natives.
Centennial RV is about the nicest park in the Montrose area...plenty of elbow room and it's well run. Now, if they could just do something about the wind... Headed for Priest Gulch on Friday.