We have been to AZ Spring Training in the past and know that if you will have children under 18 with you your campground choices will be very limited. Most cg's are 55+. Ballparks are located on the east, northwest, west, southwest of PHX as well as Mesa, Scottsdale and Tempe.
Which teams are you interested in watching?
Most of the ballparks are quite new and comfortable with seatbacks. Look for seats which will be shaded from the afternoon sun. Sunshine can be intense in March. The later you attend games during the spring training season the more likely you will see the big leaguers rather than the farm club players. The big leaguers generally leave after the 7th inning and the games may end in a tie!
I suggest that you find out the schedule of your favorite team(s). Schedules and tickets become available on the internet sometime after January 1.Then search for their home field location. Look for a cg near that ball field at
www.campgroundreviews.com. All the ball parks are within about 75 minutes of each other. Senior volunteers are friendly and helpful at the field. The games are popular so we always buy our tickets in advance.
Sorry I cannot be more specific but I cannot remember all the teams which play in or near PHX.
Have fun!