Serious Eats - seriouseats.com

if you want excellent italian you can always do lidia's in the strip district, although it is on the pricier side, it's really worth the money.
http://www.lidias-pittsburgh.com/#

buca di beppo is a national chain, but it'll be in the family style you're looking for. there's one in station square and another a little farther out at robinson town centre.

girasole in shadyside is exceptional for italian too: http://www.733copeland.com/

there's also a spaghetti warehouse on smallman street, if that floats your boat. (personally, i think it's foul.)

as for a fun, delicious post marathon lunch i suggest molly brannigans up in mt lebanon. if you go, be sure to get the boxty...i'm drooling just thinking about it!
http://www.mollybrannigans.com/locations/pittsburgh.asp

if you wanna go traditional pittsburgh-there's always primanti brothers. lots of locations, but you should try to do the strip district location. however, your picky dad may not be into it.

pamela's is delicious...(mmm, pancakes) but it's always super crowded, so be prepared to wait.
http://www.pamelasdiner.com/

i could go on and on, but i think that's a good start!
have fun & good luck getting up heartattack hill in oakland-there's a reason it's called that! my brother ran it a few years ago in a little over 4 hours, then his toenails went black and fell off. i leave the running to you-lol.

I don't have Italian rec's for you, but Pamelas is WAY overrated. Go to DeLuca's in the Strip district if you want a diner. Primanti's is classic pgh, and if you want a non-Primanti's sandwich and cheesesteaks, hit up Uncle Sam's on Forbes in Squirrel Hill (they have sweet potato fries!). Casbah (on Highland Ave on the shoulder of East Liberty and Shadyside) does mediterranean (pretty 'safe' for picky parents). It's a little pricy and their Sunday hours are brunch 11-2/dinner 5-9, so it may not be a good bet depending on your schedule, but it's one of my favorite places in the city. All my other favorites, aren't very picky-safe :P

And if all else fails, McCormick and Schmick's (a chain, ugh, I know) on the south side is very parent-safe - it was the only place my parents and I could mutually agree on for my graduation dinner. Good food, lots of variety: I had seared ahi tuna and my grandpap had meatloaf!

Good luck with your race!!

Sorry, Primanti's is awful, don't go there. It is way overrated and I think it is pretty unfortunate THAT is what Pittsburgh is known for. I second Lidia's and Giralsole. Girasole is in Shadyside and a lot closer than the strip district for where you are staying. Also, for lunch, I would highly recommend Church Brew Works which is in Lawrencville. It is an old church which has been renovated into a spectacular place. They have pierogies on the menu every night, wood fired pizzas, sandwiches and other entrees. If you are in Pittsburgh you have to go here!

I really like Legends! They serve fresh bread with herbed olive oil for dipping, which you can buy by the bottle. You can see the menu on the website.

http://www.legendsnorthshore.com/

Also see: http://www.seriouseats.com/talk/2008/03/yeah-pittsburgh.html

@cycorider: There's a half-marathon in Pittsburgh coming up!? Which one?

Thanks so much, everyone! I've been looking at menus for the past hour now. And yes, Susquehanna, it's the Spirit of Pittsburgh Half!