There is a big difference in some a lot of things at DLR. The train cannot be boarded persons who cannot climb steps. As stated lines are way different leven at DCA where the California Screamin usually is mainstream until you get to the elevator but at times they send guests through the exits. The matterhorn was through the right side exit and Dumbo was through the exits. Space Mountain require going all the way to the bathrooms and then down hallways. Pirates is through the exit and a rather narrow hallway to the dock. Big Thunder was through the exit also and also rather narrow for two way traffic.
DLR is wheelchair friendly but you may have to do some things way different from WDW. You can take the train around the park which helps like I would take the train from New Orleans Square to Tomorrowland. The monorail connects to DownTown Disney where you can dine or go to the hotels. It can be almost half a mile walk to get from the farthest hotel room to the monorail. At WDW you have busses centrally located but with DLR there are no transportation to the main gate and the only other option is the monorail.
I suggest going left and having someone get a fastpass for indiana jones then take a quick trip on the jungle cruise. Fastpass will not work on most rides at DL as most rides are seperate exits. Fastpass is way faster for the disabled who can do the stairs and walking though. Mansion has steps at the entrance to the mansion but otherwise they use an elevator. AS with WDW you should have a second person behind you on the autopia to preven whiplash or other spinal jarring, been there and remember the pain.
The nurse's station is at the hub across from Casey's Corner and near Bug's Land area near the wharf. On the Sun Wheel disabled guests can transfer to the swinging car seat or stay in their chair on the stationary one. The Hyperion theater has disabled seating but if you want the second level you have to tell the CM. At DCA the path on the right from Soarin to the Boardwalk passes the hotel where you can exit for lunch and that is a bit steep in places. Hollywood is flat but around the bear mountain is a good work out on that right side.
DCA has wide streets everywhere but not much shade at times. DLR except Toontown is much narrower and more congested. I would go right or left in a circle. I used to do adventureland, frontierland, take the trail past Big Thunder Ranch to Fantasyland then to ToonTown then take the train over Tomorrowland and finally back to Main Street. Alternate was tomorrowland, fantasyland, toontown, train to New Orleans Square, from there do New Orleans Square, Splash Mountain, pop over to Jungle Cruise then through the gate by the bathroom to Big Thunder where I could go back to Fantasyland or other land or home.