I do have a web page on vancouver with a section on its RV Parks. I am sorry to say I am a bit remiss in keeping it up to date. Offhand I would say the park in Tsawassen near the victoria ferry terminal may be the best bet since it is attached to waterslides if you are going in summer. Transport into Vancouver from there means you need a car to get to a park & ride. Vancouver has an extensive rapid transit system of subways & elevated trains, and it is best to use those to get downtown. Also there is a large park just off Hwy 99 (I-5) at the King george exit 5 km north of the border crossing. It has access to the beaches of White Rock, and and frequent easy bus connections to the subway into downtown Vancouver (Bridgeport station on the Canada Line, or to King George Station on the Expo line). Cariboo Rv Park in The suburb of Burnaby is in walking distance to the Millenium line. It is opposite Burnaby Lake Park which has many walking trails. It also has an indoor pool. The other alternative is Capilano RV park which is under the Lions Gate Bridge which connects West Vancouver with downtown. If you have a tow car, it is easy to get to Stanley Park from there. Anyway the website is (in my signature line).
Feel free to phone me for advice after May 7. 604-200-1342. Until then I am RVing in Mexico.