I'm not familiar in real life with the layout of Hawaii roads. Are the main roads accurately modeled/mapped in Flight?

Yes, in general, they are correctly placed and sized. Some bridges and other elevated structures are missing (roads just drop into canyons and climb back up the other side, or overpasses and ramps are not there), but they mostly got it.

 

I'm not at home right now, but I would suggest checking the sectional charts for Hawaii on skyvector.com. This charts include the roads that pilots can use for VFR navigation and you can try cross referencing them with flying around.

 

I haven't done this myself yet. I do know that when I was hunting for one aero cache on the big island, the roads did match very well with a tourism map.

Awesome! Another leg up on the base FSX package.

Why don't you get GMap for Flight? You can interactively see the roads you are flying over.

I've successfully navigated around Oahu using only my knowledge of some of the main arteries from Test Drive. It's surprisingly accurate, especially the lovingly rendered elevated highway through the ridge. :im Not Worthy:

I've successfully navigated around Oahu using only my knowledge of some of the main arteries from Test Drive. It's surprisingly accurate, especially the lovingly rendered elevated highway through the ridge. :im Not Worthy:

 

It's funny how you tend to see things in a different proportion out of the sky... I've played Test Drive Unlimited (1 and 2) in the past and when I downloaded Flight I first thought the free big island was the island on which TDU was situated. I was utterly surprised to find out (after quite some time...) that Ohau, which seems soooooooo small in Flight, was the same HUGE island I've been driving on in TDU...!

I've successfully navigated around Oahu using only my knowledge of some of the main arteries from Test Drive. It's surprisingly accurate, especially the lovingly rendered elevated highway through the ridge. :im Not Worthy:

 

That's the H-3 freeway, and was my daily commute to work and home for seven years. It is a really beautiful drive. :Peace:

 

There's also a good hiking trail along the ridge to the north side of the highway, Aiea Loop Trail, starting up above Pearl Harbor and heading up to the peaks. Incredible views.