thinking of visiting fuji 5 lakes and hakone as well. should i do it in 1 or 2 days? 5lakes or hakone first will be better if its a 2 days/1night?
This is what I feel ...
1. Depending on time of year, Mt Fuji can be hidden behind clouds half the time. So having more days may give you better chance to see the mountain. Staying overnight will also allow you to wake up early in the morning which usually has better chance to see mountain too.
2. There is this famous theme park
Fuji Q Highland which IMHO is the best theme park in Asia (USS doesn't even come close

) with the famous haunted house and a great concentration of rides (in fact 4 super coasters which broke several world records at their times).
If you decide to visit here, you'll need 1 full day taking into account the long queues for each super coaster. Also some of the main attractions (esp the Fujiyama) can be closed for the day due to strong winds/weather so you may have to wait another day to complete all the main rides.