Also, possibly something like 35 to 100 would provide more flexiability, though possibly impossible to find.
I just noticed that part. Actually, they're not too hard to find used, and you can sometimes get them at discount prices, just because a lens starting out at 35mm is not very popular on an APS-C size sensor, because it would have the same angle of view a lens starting out at roughly 53mm on a 35mm camera, and most users want something starting at wider in similar zooms.
Look at the Tamron SP (Super Performance) 35-105mm f/2.8 Autofocus Lens. They made these in most popular camera mounts. It's got better optics compared to the newer Tamron SP 28-105mm f/2.8 (which would be another option and you can buy these brand new), and it's a little smaller and lighter compared to the newer 28-105mm f/2.8 (although it's not a "light weight" by any means).
I think I'll hang on to my Tamron SP 35-105mm f/2.8 AF Lens in Minolta AF mount that I got for $119.95 used from http://www.keh.com
a while back. It's good enough for my limited needs at a fraction of what most newer f/2.8 zoom lenses would run (and this Tamron was the EISA European Lens of the year for 1992/1993). They're selling for more now (but, the prices for them are still not too bad).
However. since he'll probably want a walk around lens for general purpose use, it may be easier to get something more versatile that could double for multiple outdoor uses. For example, a Sony DSLR-A700 kit with a Sony DT 16-105mm f/3.5-5.6(D) Autofocus Lens. That would give you roughly the same angle of view you'd have using a 24-158mm lens on a 35mm camera.
Sony DSLR-A700 kit with Sony 16-105mm f/3.5-5.6(D) Lens at B&H for $1,599.99 after $200 instant rebate
With a 12MP sensor, he should be fine with the quality of that type of lens at typical viewing and print sizes (even though the sensor is probably outresolving it), as compared to the 18-55mm kit lens he was using on a 4MP D2H, and it would make for a smaller and lighter package.
See this article for someone using this same Sony A700 body/Sony16-105mm lens combination for for a variety of purposes including outdoor sports:
Sony A700 Field Report using a Sony DT 16-105mm f/3.5-5.6(D) Autofocus lens
Then, spend another $400 or so and grab a Tamron (or Sony) 28-75mm f/2.8, or Sigma 24-70mm f/2.8 AF lens if you want to go with a new lens for indoor use without a flash.
Or, you could get a brighter prime instead (new or used). For example, keh.com has both Minolta 50mm f/1.7 AF lenses (in the $100'S) and Minolta 50mm f/1.4 Autofocus lenses (In the mid $200's) in stock now. You could also buy a new Sony 50mm f/1.4 AF lens for around $350, or a used Minolta 85mm f/1.4G AF lens for around $800 if you wanted something longer and brighter in a prime. KEH.com has some now in the 700's (just look under 35mm, Minolta Autofocus for lots of listings). Here's an example:
Minolta 85mm f/1.4G Autofocus lens in EX condition for $789 from keh.com
Or go new with a new Sigma 70-200mm f/2.8 for around $800 if you want a longer f/2.8 zoom instead.
You've got lots of choices. ;-)