Have you looked at how many ff miles are needed to get back home?
Have you looked at the award rules of these ffp's? Some do not allow stopover on one way awards. Will be priced as 2 awards.
And then there is the big problem of availability (as post above). Availability can disappear in minutes as others are also looking for awards.
You should also find out the cash price for a ticket home from NRT or from an intermediate point. (this $$ may scare you !!)

From http://www.flyertalk.com/forum/infor...help-here.html
Awards assistance tools (use at your own risk. May not be up to date. These are not recommendations)
- AwardAce: Compare Award Redemptions Across Airlines In Seconds -->http://www.awardace.com/
- Economical Excursionist's Tools to compare Frequent Flyer Mile Redemptions --> http://www.flyermiler.com/
- http://www.expertflyer.com/ is a common tool used on FT. There is a $99.99 annual fee.
- http://www.travelcodex.com/how-many-...chart-search/? (commercial blogger)