Your dog is a member of your family, so why exclude him from your fitness routine? Why exclude him from your fun road trips. Madera is less than an hour drive from Fresno so is a fun road trip but still low cost. There are several stops along the way for you to give your dog a water break. You take highway 99 North from Fresno to Madera California. There are at least 3 truck stops with easy on and offs spread out about evenly along the way so you can give a dog unaccustomed to driving a chance to take a dog break.
The Fresno River Trail is a great trail that is part of the Rails to Trails system. This hiking trail is amazing for hiking with your dog. The trail is at Riverview Drive near Westberry Blvd and has ample parking there. It ends at Tulare Street and at that end also has parking. What is amazing is that it is paved the entire way so there is minimal risk of hurting the dog paws while hiking. You do not even need dog boots when you are hiking this trail. If you do not like hiking you can even go inline skating with your dog. Based on personal experience going inline skating is great for a more active dog since they may not get tired as quickly as you do.
The entire trail is 3 miles one way and it is graded as a Greenway non-RT trail. What does this mean? It means it is a two lane trail with a dotted line in the middle so when you are hiking with your dog and encounter another dog you can easily keep the dogs apart. It also means that it is a smooth paved hiking path with minimal change in elevation or high slopes that at times goes underneath overpasses. It is even accessible for wheelchairs.