Being single is a patchwork quilt of positive and negative experiences and feelings.
Most people point to time and freedom as the top two benefits of being single. With those resources, singles can devote themselves to knowing God better and serving Him, can explore their interests, live a lifestyle of their choosing (be messy, sleep in late, splurge, etc.) and more.
The drawbacks of singleness include aching loneliness, discrimination due to one's single status and even growing self-esteem issues. As great as it is to have my alone time, sometimes I have too much of it and need to interact with people who know me well. And as wonderful as it is to have freedom, I also get ignored socially by married and families who either don't know what to say to me, or would rather just talk to other marrieds. And that starts affecting my self-esteem.
BTW, I agree with mina (you go, girl!) -- it gets REALLY tiresome to be "the good little soldier," doing everything by yourself and trying to keep a stiff upper lip, pretending everything's fine when it's not. And it's also tiresome to have people view you as some sort of failure for feeling that way. It's so easy for marrieds to be judgmental sometimes.
Halls, I'd encourage you to teach your women to use their single years to develop a solid habit of spending time with the Lord. That relationship will be critical to them in all areas of their lives, whether married or single, with or without kids, at work or at home.
Then I'd recommend encouraging them to get out there and DATE. Don't fall prey to the idealist notion that husbands will fall into their laps. It's not the way life happens. Oh, and to date with discernment.