I hopped on Craigslist last night like I always do, looking for cheap things that I intend to purchase. Found a sweet bike trailer FOR $35 that was dusty as hell, but works just fine. Came complete with every thing I needed to hook it up to the bike and hit the road. I need to pump up the tires, but otherwise, it tracks straight and moves down the road well.
The dog park is exactly 5 miles each way from my front door. Our wonderful puppy, Geronimo is only good for about 3 miles at 11-12mph before he's ready to walk. Takes me too long to get us to the park where he gets to romp around with his buddies.
Problem Solved. Average speed there and back was 14.8mph hauling a pretty stout trailer and a 36lb Labradoodle named Geronimo.
Bonus, when we need to get places a bit faster, he rides the motorcycle instead.