I did this a couple years back. I went all out and did a 220v 5500w with a control box, 15 gallon pot, a small 110v and small pot to act as a heat source for a HERMS and a march pump to move it all around. 220v pay off in shorter boil times, but you could do 2 110v on 2 different cictuits too.
There is no reason you couldn't simply replace/retrofit the pot/kettle you use on propane with a heating element and call it a day.
As you mentioned steam is a MAJOR concern. Mold will become a serious possibility. You need to consider if you can find a way to vent it. (There is a 75 dollar vent hood thread in this section section you might want to look at). A 7 gallon to 5.5 gallon boil will put 1.5 gallons of water into the air in one room, that is enough water for a normal sized entire house. In my experience it gets worse if you do multiple batches in a day, batches on back to back days and you are going to have an issue with anything that is requires significant boil downs (I did a couple where I needed to boil 15-16 gallons down for a 5 gallon batch, one was alot of popcorn which required multiple mashes and one was a 45lb grain bill for a 1.2 OG which required a couple runnings due to small mash tun) That much water evaporated without a vent is a bad idea.