Hi. I attempted (only 52% complete at the time) this route in 2021. I am from the DC area, but started in La Push, WA, with home as the end goal. The largely completed portion between DC and Weirton, WVA is something I've done 10+ times as it is local.
There have been improvements/additions since then. At the start, I was negotiating loggers in some parts of the ODT as the bike trails come along, segment by segment. I think the trails are close to fully implemented now. At the time, I carried 4x500w Bosch PowerPacks + a 110W solar panel on a trailer, so I did not experience charging issues until the eastern half of the PCTC. The western side (up to Snoqualmie Tunnel) is easy, passing thru tourist traps areas like North Bend. East of the Columbia River, this trail gets remote. The Beverly bridge has since been completed. A few observations. Loved the state park (Wanapum) on the western bank of the Columbia, right before Beverly. Beverly and further east gets a bit hardscrabble here and there. I remember registering online to get a combination to the locks on periodic gates ... not all of them unlocked. It was a hassled to unload/unhitch to get past them. Also, I seem to recall signing in at an unattended booth and asserting citizenship to cross portions of the Yakima Training Center. Given the current climate, I would research to anticipate changes.
So, locks that would not open, sections of trail that went to nowhere w/ backtracking required (battery!), homeless encampments and 'infrastructure' that no longer exists were features along the way. For example, in Rosalia, I found a city park with camping sites, but the pedestals had been pulled out of the ground. I was told the city was getting rid of camping due to yahoos from Spokane tearing up the place on weekends. OTOH, it looks like it is allowed now with reservations in advance. I loved the site in Ralston. Camping was not a thing back then, so my unofficial sleeping on the grass was sprinkler-interrupted. I found an outlet on a pole nearby. Looks like they welcome campers now.
Eastern WA sets the tone for the entire way. Research, research, research, and do not assume nothing has changed. The small towns are mostly agricultural. Many public outlets are locked off. If not explicitly available for public charging, I ask the city and offer to pay when businesses are non-existent/unavailable. In one town in Idaho (and off-trail excursion) my formula for finding camping at a county-seat fairground failed. No lodging in town. I called the city, and they gave me permission to camp in their city park with bathroom access, electric, and most important: instructed the local police to leave me alone. The city stated explicitly that I was accorded this hospitality because I asked instead of making myself welcome to their resources. Price of electric is spiking everywhere, so I'd be even more mindful now.
Idaho panhandle section is back to the world of finished bike trail w? bike shops, tourists etc. Lovely scenery, wonderful people, new business were springing up to take advantage of the bike traffic.
Montana - challenging, which goes for all of the mountain west. The trail sections are dominated by ATVs which go fast and do not expect you. Many portions are rutted due to this use and barely bike-navigable. Outside of major areas like Missoula, Bozeman, etc, I bought bear spray and started talking to locals about where to camp/overnight. Everybody seems to know/track bear sightings "oh, there's one that comes down for the cherries getting thrown out every night back here" so I relied heavily on local tips. This will be the first state where you start to customize your route to compensate for lack of trail.
WY - hopeless. I don't even understand how they will implement the trail as planned given the lack of pre-existing rail in the proposed areas. There are long stretches without any services at all. In past trips, I managed sections like this in NV/UT up to 150 miles, but this exceeded my capabilities. I'm talking about the section that drops south for a while before you head east again. I took advantage of a truck ride for part of it. Also, once you hit Cheyenne and points east, you are fighting wind all the way into Western Nebraska. You can't even roll down a hill. If I were to do this again, I would really carefully plan from Yellowstone to the Cowboy Trail in NE.
The Cowboy Trail is always a mixed bag, research before you go. Trestle detours, goats heads; you'll be jumping on the paved road as needed. Once you hit Omaha, and Pottawattamie County, Iowa, you are golden. For the non-trail portions of Iowa, well, you have 99 counties, each with county parks set up for camping with amenities. Expect a lot of RVs. I love Iowa, people are so nice.
The eastern half of the US is much easier except for sections of Appalachia, but nothing that is not manageable. Feel free to ask questions and jog my memory.