but, I feel that all gates, walkthrough, should be about three feet, which is the width for a mower and wheel barrow. I always install three and sometimes four hinges.
I like to build my gates just like the fence with their rails, but add the diagonal bracing to make the letter, "Z". This does support the gate some. I make sure that I sink ultra deep the adjoining posts, especiall the one holding the hinges.
If installing double swinging gates like over a driveway, I like to install that pnematic wheels to take the swing weight of the gate and also make the framing out of angle iron.
Gates are very seasonal variated. In other words, when the earth is dry, the gate will seperate and not catch, when wet it will bind. Gates must always be tweaked a bit to work properly. Gates also must require constant maintenance.
Many gates fail due to not enough support and too few hinges and posts not deep enough.