This is the hardest period. If you are going to be continuously adding money it's okay to be 100% stock up to 10 years out, then subtract 10% for every year under that (rule of thumb).
Vanguard makes stock/bond funds in 20/80, 30/70, 40/60, 60/40, 60/40 tax managed, 80/20, and the Wellington/Wellesley types. You can also use intermediate term corporate bond or high yield tax exempt to get a relatively safe investment that approximates a more conservative balanced fund.
There are also DIY options. Use a 60/40 US/Int'l stock allocation, and subtract 10% for every year under 10 years to do a custom glide path. Use a single date treasury STRIPS bond maturing in 3-10 years so that your bond allocation will automatically become safer as your date approaches and keep buying that same bond CUSIP.