If the current door latch is intact enough to hold the door closed for you while you are camping in it, the easiest way to make it secure from others and from opening while traveling is to add a deadbolt. I did just that and it works great. I used a medium cheap bolt. Most have the optin of the 2 popular setbacks. You will need to drill a hold in the door and mount the catchplate to the frame but that is not terribly difficult. You will need to get a bolt that has a "thick door" adapter, since the Burro
door is 2 1/4"thick at this point.
Once this is done you will have great security and the door will not pop open when you are traveling and you can adjust the closure with the placement of the catchplate so that the door closes tightly against the seal and does not leak.