A lot of parks tend to limit where I can go with my dog. What are some resources that will help with my trip planning? It's sometimes hard to find if dogs are allowed or not.
State and National Parks as a general rule only allow dogs in campsites (always attended) and on paved surfaces. This is a huge negative for most dog campers. For me, I'd only choose to bring my dog here under 2 conditions: "Party camping", where you're spending 95% of your time in camp, or if the dog is a puppy/senior...when you just aren't able to spend a lot of active time on trails. So in general I don't think its worth bringing dogs to state and national parks. They are awesome and are totally worth spending time there - but its better to leave the dog home with a friend.
On the otherhand, don't forget about our awesome National Forests, which generally DO allow dogs on trails. There are options for proper campgrounds and backcountry camping. Plus, you tend to be nearby the famous parks, which allows you to avoid big crowds but still recreate in beautiful country.