I have done your stated trip several years back. Washington DC to San Francisco
We chose this route because I had family in Atlanta, GA, we could purchase Barbecue for breakfast lunch and dinner (SFO we had Sushi at Godzilla Sushi); between ELP and TUS there is a low altitude pass to fly through south of Truth or Consequences.
- headed west bound its almost impossible to make your fuel stops because of headwinds. Many stops are 3 hrs distance. Heading into a valley for fuel may out you into the situation of climbing to altitude for :45 minutes, then not making the next fuel stop. West to East you must select and at airports which are at 3 hr intervals.
If available, I would select a C-182 for its Fuel capacity, if it have a fuel management computer you could push some further distance legs. I'd still probably take the southern route, head up toward San Francisco, Lake Tahoe, Jackson Hole WY, Livingston, MT, Montrose, CO, Aspen, CO (just some ideas not a route).
When accepting our IFR clearance we would request a VFR (visual) climb; departing PSP it took 1 Hr to reach cruise altitude in the C-172.
Hope this gives you some ideas. Hope you have fun
Aug
7/29 KJYO - GSO 3.1
7/31 GSO - PDK 3.2
7/31 PDK - GLH 3.5
7/31 GLH - DAL 3.0
8/1 DAL - BPG 3.1
8/1 BPG - MAF 3.2
8/2 MAF - ELP 3.3
8/2 ELP - TUS 3.0
8/3 TUS - PSP 3.5
8/3 PSP - LVK 4.4
------------------------------
8/4 LVK - VCN 3.5
8/4 VCN - SDL 3.5
8/5 SDL - ELP 4.4
8/5 ELP - TDW 3.6
8/6 TDW - FSM 4.0
8/6 FSM - MEM 2.9
8/7 MEM - N54 2.5
8/7 N54 - CRW 2.7
8/8 CRW - JYO 1.5