To touch on one of your other questions - some of the easiest road accessible fishing is found along the Parks Hwy streams north of Anchorage - good fishing within a 1.5-2 hr drive. For sheer numbers of fish, the pinks and chums start filling in the last week of July into August. By August 1st you'll be able to see salmon from the Parks Hwy bridges on Willow, Sheep, Montana, etc.
Willow Creek State Rec area has easy trails to the river and bank that is accessible. It will be busy with other people fishing, but you're not going to find a lot of solitude with limited mobility off of the road system.