SEO Keyowrd Domain Questions

I got a question. Lets say you have a client with a domain that represents their business like www.BobsShop.com and his business name is Bob's Shop. But Bob sells trout fishing equipment. Does it make sense to try to get a domain like www.bobstroutfishing.com or www.fishingtroutwithbob.com and then point that domain to the existing site, but do SEO for the new domain. My question all in all is. If you have a domain that does not have the main keyword in it, whats the best course of action to do SEO.