Try the NH3 only if you were 'bored' of the endless straights on the NH8. Because NH3 is NOT all 4-lane highways. The road between Gwalior and Dewas i.e. almost 460odd km is 2-lanes. Not that it takes a lot of time since the road condition is generally good and the traffic is low. Finding help/accomodation/food is easy enough as this is a NH and there are major towns every 100km. Following the NH3 all the way till Dhule, you need to take the exit towards Manmad / Shirdi 32km ahead of Dhule.
As for what kind of traffic you will encounter there, please read this post I wrote 20odd hours after leaving MP. This will tell you why I found NH3 'exciting'
http://www.xbhp.com/talkies/xbhp-off...tml#post578857
The post is dated February '11. Since then, the road condition has improved leaps and bounds. There was at least 250odd km of 4-laning under construction back then. That work was completed back in May.