Texas - dfw to downtown Dallas question

What is the fastest routing by mass transit, buses, trains, etc. to get from dfw to downtown Dallas? I connect through dfw on aa very often, but never long enough to get to Dallas. I want to see the JFK assassination area first hand (book depository, grassy knoll, Dealy Plaza, etc) first hand, and would try to schedule a connection long enough to get to Dallas and investigate and return. Anyone have personal experiences with a routing?

By mass transit?

Take the shuttle bus from the terminal to South Remote parking. Then take the TRE Shuttle to the Trinity Rail Express "Centerport" station. Take the TRE train (note, does not run on Sundays) to Union Station, and walk a block to Dealy Plaza. I'd allow a half hour for the 2 shuttle buses; Google will find the TRE schedules online.