I think your situation is very promising. Saving is probably the most important factor in achieving a financial goal and working on a plan. You are doing both.
Keep in mind that 5 years is really a fairly short time frame to be investing in stocks. In 2007/2008 stocks lost 30-50%. Look at the amount of equity in the funds you select and see if losing 30-50% at year 4.5 is okay. We had a rapid recovery and maybe lucky. There are rewards in stocks because the risk is real and there are no guarantees that the next time will be like the last time.
I like the Life Strategy fund and may use it myself in the near future. It is a 3 fund portfolio. See this discussion:http://www.bogleheads.org/forum/viewtopic.php?f=10&t=88005