I have posted many times on the wife/girlfriend bike. I'll summarize some of the crucial criteria here.

1) COMPACT CRANK!!! Many entry bikes and womens bikes come with triple cranks. Do not get a road bike with a triple, period. I know Iowa well and the rollers there do not need a triple - just the appropriate range compact. Likely the compact will come with a 26 or 27 cog in the rear too.

2) Lightest wheels you can get. Again, lower end bikes come with heavier bulkier wheels. It's awful that some of use 180+ pound tall guys are riding sub-1550 gram wheels but then stick our 100-140 pound women on those awful 2000+ gram wheels on entry road bikes. Lighter wheels+lighter tires+lighter tubes makes for a spry bike and a happy woman. At the same time, do not get any wheels that have rubber bearing boots on the ends. Those things equal low quality and on many wheels can drag horribly.

3) Looks. She must, must, must like the color scheme/looks of the bike. Don't settle on the ugly one because its on sale.

4) I think compact frames work better for newer road riders as they feel more comfortable with the standover. Most frames are now compact but this should be on the list.

5) Don't necessarily settle on the stock saddle. Be prepared to buy a different saddle. Trek and Specialized actually both make nice womens models in different widths, and the dealer can use their butt pad to determine the best width. In some cases you may be able to have them trade out the saddle for the same one in a different width if needed.

6) Road pedals. Don't instantly think a newer female rider should be on SPD cleats and shoes and consider actual road pedals like LOOK or Shimano's versions.

7) Finally, women specific designs can be great, but just remember she could actually fit better on the non-WSD bike. However, be careful and refer back to #3.