I have a old, thin-walled house with external galvanized iron dwv
servicing the kitchen sink and dish washer. The dwv is rusting through
in spots and needs to be replaced. The nearest location in the house
where a vent pipe can be run internally to the roof is at the utility
room ~30' away. The other option is to run another external dwv pipe.

If I were to put in a island vent under the sink, is 30' too far of a
horizontal run for the foot vent? If that's not an option, what do
people generally use for external dwv now?, abs, pvc?