Downtown is generally pretty safe for walking, at least during the daytime. I used to ride the DART train from the North (Red/Orange line) and am familiar with the areas around most of the stops.
If you’ll be riding the DART trains, Mockingbird Station has a lot of stuff right on top of the station itself- one of those mixed-use developments also called “Mockingbird Station”.
A bit further north, there’s LOTS stuff within a fairly short distance of the Lovers Lane station. Fairly short being inside a mile, with a lot being even closer.
I wouldn’t go to the West End though, or if I did, I wouldn’t get off at that station. It’s not particularly safe at that station. Lots of crime and really sketchy types hang out there. I’d honestly walk over to the JFK memorial/Elm St. than take DART and get off at West End.
After Lovers Lane, Park Lane is right next to a big shopping development (Shops at Park Lane) and Northpark Mall on one side, and on the other it’s very close to some of the lowest income, highest crime apartment areas in town.
From there, the next few stations (Walnut Hill, Forest Lane (my station), and LBJ Central) are pretty sparse on the stuff nearby; normal suburban stuff, but nothing special. Spring Valley is a short distance from the biggest Middle Eastern/Muslim area in DFW - there are a lot of restaurants over there, but I have only been to one or two. I mostly frequent the grocery stores(Jasmine & Sara’s).
Arapaho Center station is weirdly placed; a half mile back and it would have been within walking distance of downtown Richardson, and with it, one of the largest Asian restaurant concentrations in DFW. If you do go up there, and decide to walk, Jeng Chi Restaurant is fantastic.
After Arapaho Center, the only other place I would consider would be downtown Plano (Downtown Plano Station) and eating at Jorg’s Cafe Vienna, which is a Austrian restaurant (meaning somewhere between German and Hungarian) or maybe Lockhart Smokehouse, but I think I’d go to the one in Bishop Arts on Davis St. before I’d go up to Plano for it. I think I’d hit Terry Blacks or Pecan Lodge first if I wanted barbecue anyway.