WM Standpipe/trap

Great forum. I have been using this forum for years now as a resource but this is my first post:

What is the maximum horizontal distance allowed between a WM vertical standpipe and it's trap? Currently, my 2" PVC standpipe goes directly into the trap and then 45's down into the crawlspace to join a 2" drain line, approx. 12" drop. The 1.5" vent ties in about 6" upstream of the WM drain on this same drain line. The standpipe is about 3' tall, the trap is almost on the floor. I need to move the standpipe about 3' down the same wall. Can I just move the standpipe and add a 3' horizontal run over to the existing trap?

I will slope the "horizontal" as usual, but should I expect any stinky trouble to occur by adding this run? Any other problems you see with this setup? I will post a picture if needed, but I think it's pretty straightforward.

Ideally I would relocate the trap too, but the glue-up is inaccessible due to brick veneer wall with kitchen cabinets on the opposite face.

Thanks

The stand pipe should go directly into the trap then from the trap to a T with vent above and drain below.

If you have access below the floor you can run the stand pipe through the floor directly into a trap under the floor and place a T on its back about 12" from the trap with AAV about 6" above the drain pipe and tie it all into the existing drain.

It should all be in 2"