Yeah, don't do the dogtrainingbackpackingjumpingjacksxxxporn.com domain name trying to target all those different keywords.
Look at wikipedia, they rank for almost everything and I'm sure most keywords don't have wiki or pedia in the search.
Once your site is larger than a micro niche it's better to have a short and memorable domain name than trying to fit all the keywords in it. I've got a site that's 700+ pages now and I know for a fact the domain doesn't contain even a fraction of the keywords I rank for. I also think it helps for type in traffic and branding purposes if the domain name is less than 10 characters.