Installing an upflush toilet with a macerating pump. The pump has a 1 inch discharge. Can I connect the 1 inch discharge to a 2 inch line using a wye that travels 3 feet and ties into the 3 inch line, or do I need to connect directly to the 3 inch line using a wye

You can connect into the 2" drain... no problem. Install a wye into the line and then another wye to pick up the macerator discharge on the branch... install an end clean out on the run of the wye fitting to finish it out. Make sense?

Mark