I'd maintain a 2x pattern when you replace the spokes and rim. (note I suggest both). Get a wide box section (double wall) rim for most strength/stiffness nd use a wide a tire as will reasonably clear the frame/fender. Why stay with 2x? because the hub now has the spoke holes "worn in" by the original spokes. I like to have replacement spokes fall into the same spoke hole wear indents so to limit the hub's further wear also with a touch more contact between the spokes and flange there's a bit less focusing of the stresses on the spoke's elbow. The evenness of the new spokes' tensions and the rim will be a bigger effect then 2x or 3x.

Remember that whatever you do with this bike that it carries your load will place more stresses on it, all of it's parts are working harder. As mentioned your riding style can greatly impact (bad almost pun) the longevity of the bike. One pot hole or lack of proper air pressure will negate all this wheel investment. Andy.