The D300 and 70-200 VR will be a very good combination and if you need the extra length go for a 1.7 converter. desantnik is a member on here and I'm sure he uses this combination and his results are fantastic.
Hehehe thanks for the big up
I don't often use that combo really. I think I've done it twice and only got good results once. If you must stick a TC on make sure its a good bright (ish) day and ideally use a 1.4x not the 1.7x and definitely not the 2x!!!
The thread you highlighted I was actually using the Nikkor 300 f4.
With bikes its not very often you'll see me with the 70-200VR in use, unless its MX or you can get stupidly close (not very often even with a media pass to be honest, well, not unless you just want side on pans... :nono
Usually I'm shooting the 300 f4 with or without TC's - without is much better...
If/when I can afford it, I'll be punting for a Nikkor 300 2.8, thats the daddy when it comes to motorsport really... chuck some TC's in the bag and you are sorted.
But anyway, the ideal motorsport kit bag is a 70-200 like you have, a 300 prime (f2.8 if you are rich) and some TC's for when you are desperate. Just make sure you take all of that out with you and change to whatever you need for the shot as you find it.
Sorry, to answer your question directly - yes the 1.4x and 1.7x work perfectly with a Nikkor 300f4 and D300.