Overland Hanoi - Sapa --> Tay Trang border - Luang Prabang

Hi. Intending to travel overland Hanoi --> Sapa --> Tay Trang border --> Luang Prabang, next March. There will be six of us so am thinking of hiring a minibus or 2 x 4WD with drivers for the one-way trip. Haven't got much time for this leg of the trip so was thinking 4-5 days with the final day comprising the one day boat trip from Muang Khua down to Luang Prabang. I know this will be a lot of time in the vehicle but that route sounds interesting.

Do you know of good agents in Hanoi who will rent vehicles with drivers for such a trip?
Is 4-5 days too short a time?

It is too short if you want to get out and stretch your legs, and perhaps meet some of the people whose country you are traveling through. Vehicles run from about $70-$100/day (with driver). MIght be a bit more for a vehicle that can accomodate 7 (6 guestts + driver). You'll pay for the two days (or one very long one) for the driver to get from LP (or Muang Khua) back to Hanoi, of course, as well.

I'd recommend hanging in the Sapa/Lai Chau area for a week - do a trek, visit some outlying villages. Perhaps a two day hike up Mt. Fansipan if that's your thing. Ths will save a lot of money and time, and you'll actually get to visit where you are as opposed to watching it through a window (much like watching TV, esp. if you're in a private vehicle). You can take the night train up to Sapa and back - nice cabin for $20/person (or less) provides transport and bed.

Of fly Hanoi -> LP and enjoy a 4-5 days in the LP area (rent a day vehicle there and you can visit a dozen great sites, either remote of not).