I used
Sanidumps.com last summer to travel from OH. to Alaska. One thing concerning was thru-out Canada and Alaska dump stations in the provincial, state, BLM and US. Forest Service are very few that actually have one. Most of the time with Sanidumps app. there are "FREE" ones at visitor centers, gas stations, grocery stores and city parks. Very important was if the locations also have potable water available.
Because I knew what route I would be following, before I left home I Googled each location on a satellite map and made notations to actually where each one was. An example might be: Town of Smithers: South end of town at the Canadian Tire store in SE. corner of parking lot.
The smart phone app. works fairly well, but it would be nice if there was a date for when the last information was posted. Surprisingly I didn't have any issues in our whole 110 day trip. Twice I did pay $5 to dump. Once at a Cabela's in SD. (dump was $5, water was free) and in Seward AK. So I would say over-all I was very happy.
I will add, if your looking for a "free dump" in the east good luck. I think my state of Ohio has 4 located on the Ohio Turnpike. They have them listed as free.