You did very, very on the price---a driveable E150 even with the 4.6 for $1500 ain't bad at all.
My own approach to buying a used van (especially in my climate) is the condition and rust level of the welded body structure, anything bolted-on of minor concern. The best thing about our E-Series is the bodies are mostly 100% swappable from one chassis to another, "ease" being a highly relative term though.
Bodies from '97 forward to EOL are so similar its almost unbelievable in this day and age of major changes every few years.