ok the most important thing to keep well maintained in an E-Series is the cooling system IMO. Make sure you give it regular coolant changes ( I suggest every 6 months ) and be sure NOT to use bore/tap water, demineralised preferably. Also if it hasnt been done for a while I suggest you change the thermostat and get a radiator shop to clean out the side tanks of the radiator.
other than that they are just as easy to look after as an older ford. I suggest you buy a workshop manual as these are a great tool. Give her regular oil changes ( every 5k )learn how to adjust the timing in self test mode and your set. Also keep the 4 speed auto well serviced as theyre not known for their longetivity
Lets go find that Hotdog tree I planted
Lowered EF Futura
Black Steelies ( too cheap to buy proper mags )