Greetings Fishhead,
The concept of using recycled blacktop over the top of a graveled driveway is no different than graveling a road and then blacktopping it - except the cost of recycled is much much lower than actual blacktopping and doesn't require steam rollers. Recycled blacktop "knits" together with some exposure to sun - and it makes a more connected surface compared to gravel. It also stops weeds from growing thru - far better than gravel does. In other words - leveling (or a small crowning) the gravel and then applying recycled blacktop helps stop rutting and makes a whole lot nicer surface for snowblowing. And one last benefit - is recycled blacktop in winter allows far improved melt and snow/ice runoff compared to gravel because its black and because petroleum based product keeps the water/ice/snow better "separated" from the ground. Your snowblower will be grateful and last much longer with recycled blacktop on top compared to gravel. And you'll have far less dust and no rock chips on vehicles.
And Aranyic: It sounds like you've come to a sane and common sense set of decisions. It may not be a 15 year solution all at one time - but then you "financially live to fight another day". LOL
P.S. Regarding Recycled blacktop used for new blacktopping activity - its a huge benefit for the blacktopping operations and the public in general. Typically most states require a maximum of 30% or 35% recycled used in the mix of new blacktop. It saves our landfills and keeps down the use of petroleum products . . . but they've also found that recycled blacktop additions to new blacktop actually makes a stronger and more durable blacktop than strictly brand new blacktop can produce. It acts as a superior binder much like sand mixed with aggregate in concrete binds better than just sand or just aggregate. And they've found that 20 year old blacktop contains about 1/3rd of its usable petroleum too. Car lots are using recycled in some cases where gravel outlots exist. Keeps dust down and reduces rock chips for them too.
AxleHub