Go ahead and take the iron, just don't smelt it, you get better yield in a factory, the coal should be grabbed with a silk touch pick. Gold also is fine to take, you still get the ore for that one too, everything else needs a silk touch.
I might have been the one who screwed up the farm, I recall falling into the channel, but I don't remember breaking any dirt in the channel, I did break a chunk above the channel in order to get out.
I'm going to be working on the rail station now, I'm putting the laketown station in the old farm, then again it would be sooo much more efficient if I put the station at level 11 where the lines are like everyone else does. If so the old farm is a great place to put the entrance. Required would be a drop shaft into water, a landing spot for a cart teleport, or alternatively a water elevator. The top level of the entrance is a good place for a small park/plaza. Then stairs going down to the rail level also, a spiral design is good to ensure the stairs stay in the general area of the elevator. Maybe an open shaft around the elevator, the stairs spiralling around the outside of the shaft, a glass ceiling over the shaft... And for good measure a drop shaft/cart porter hidden off to the side somewhere perhaps the drop shaft hidden under a fountain and the exit of the cart porter landing near landscaping centered around the fountain. For now I'll consider where to put it and dig the rails/drop shaft. The rest can wait until I get the time :p