MD-88 ATL sounds like your best option for a good quality of life, IMHO.

I was awarded the 717 to NYC in the 4 Jan Indoc class. I was awarded ATL, on the Jan AE during Indoc with a conversion of 1 Jun. I was notified today that my conversion was moved up to 1 Apr. I will be the plug in ATL on the 717 but the commute from LIT to ATL is so easy and the hassle of covering 3 airports and the weather issues in NYC, and the hotel/crash pad costs make the move to ATL worth it. Just my opinion.

I think ATL 717 gets a decent number of JAN overnights. Seniority progression would be roughly equal to the 88.

How long are folks staying on reserve in NY on the 737 and 320?

Excellent point. Of course the company can and does change schedules at will. Almost nobody likes the JAN layovers -- open time is chock full of them, including 30ish hour layovers. It would take you a while to get a line, but even on reserve you'd be able to try and YS (volunteer) for the JAN layovers.

Any best guesses on when a new-hire could get into LAX, SEA, SLC, in that order of preference?

LAX has the ER, 73N, and 717. Respectively, the most junior in each are June, August, and October 2015 hires.

SEA most junior category is 73N which is May 2015 hire. The ER is a Nov 2014 hire.

SLC has ER, 73N, and 320. April 2015, July 2015, and Dec 2014, respectively.

Take a look at the lakeside graphics link. It shows the relative seniority at each domicile.
http://www.lakeside-graphics.com/pilots_relpos.php

This is epic... thank you!

LAX - quickly on 717 and possibly on 737
SEA - quickly on 737 and E190 coming soon
SLC - Inside a year on the Airbus, possibly much sooner