Hi Hun~ I have lived in apartments/Mobil homes and houses so I can tell you that the apartment was the cheapest as far as electric. However, in an apartment you may run into problems with your son being loud if the neighbors complain. The management will only give you a few notices then you will be asked to leave if they get enough complaints.
It may make for a stressful situation. Talk with the management and see what they say, that may help you decide right there. Usually they request the deposit and first months rent before they will give you the keys.
Also remember all the cost’s it just takes to move, you will be paying closing bills at the Mobil home as you are paying current bills for the apartment. Just something to keep in mind. You mentioned grand kids, can one of their parents help you out and mow the lawn for you so you don not have to worry about it?