I have visited over 10 times.
Omagari is the king of Fireworks fes in the world.
But town Omagari(now a part of Daisen city) small area living under 150,000 people.
however Fireworks day(one night only) coming over 700,000 travelers by trains,cars(bus) from all Japan who about 50% trabelers coming yesterday or more before days
for escape bad traffic-jam and free area postion getting line in the day morning(gate open).
So impossible hotel booking near town/cities.
on the other way Shinkan-sen train or [night]bus tour(no hotels) a lot.
but not ecpensive tours sold out very fast.(if livin in japan/also as Japanese)
if really want to get tour booking must entering japan earlier recommend.
maybe one or two month before.
[Pic and video]
http://blog.xlarge.jp/_images/kaijyou.jpgmain area of river bank at 6:00pm (not peak)
bank area not free.
http://youtu.be/bcR01zJVJIoafter fes at JR Omagari sta train waiting line on 24:00.
main area to sta not so far arond 20min usual but stuck over 90min from all roads.
[Fes schedule](not 2013)
9:30 free area gate open (not wide but make line from midnight)
17:00〜17:45 day time part
18:50〜21:30 night time part
around 20:40 Sponsor part special shooting(main event)
http://youtu.be/_3YCxiv0v7Umost tour package until sponsor part end.
if I were u rent a car from beforeday and arr midnight then wait/sleep whole day in car.
but if fine day hot over 30℃ very hard travel.