I'm going to throw out some more ideas for you to consider. As others have suggested a class C might be better for you especially with a baby. I'm a little bias because we have a class C but it's so convenient to have everything along when you're out for a day of sightseeing. We have very little trouble driving in cities and finding places to park. Check my blog link for more information.
Consider buying a rental. Forum members have had good luck doing this -
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/26035008.cfm Try -
http://www.canadream.com/SearchResult.aspx or
http://www.cruiseamerica.com/buy/ Our national parks are spectacular. See as many as possible!