We have 4 young kids and I have a step daughter too. We have been in our 33 foot fifth wheel for 2 years this coming August. The first year we spent 2 months on DH parents farm, 2 months at my parents place, travelled though the US then spent 3 months on a 180 acre farm, then went travelling again through BC and Alberta. We have now bought our own farm and are on 5 acres building a cob home.
CHeck out Families on the Road, we went to a rally last year and met 15 other families fulltime on the road to, and made some lifelong friends!
We LOVE the length of our 5th wheel, some of the other families were longer but to big to maneuver and park. Ours has no slides but we fit in it well. We adapted our back area to make a bunk room where DH and I have a almost king sized bed with a crib off the side for the youngest. Then there are 3 bunks for the 4, 6, and 7 year old down below. When StepDD comes the 4 year old sleeps up with us (and does anyways quite often!), plenty of room.
We didn't pay alot for RV parks, we boondocked alot at BLM land or a variety of places, we run on solar which payed off in all we saved on campgrounds! It depends on what time of year and where you want to travel!
Here is a link to our website www.canadianfamilyrobinson.com
For travelling US look back to last year around this time
Feel free to email me with any email@example.com