My take on jump drive exits/entries etc, is that as previously mentioned the ship leaves the physical universe, spends a week within a jump bubble possibly within an alternate dimension, and finally precipitates out of jump a week or so later. Mass shadows of large objects can affect jump drives, causing a violent jump exit at the one hundred diameter limit, though jumping from Earth to Saturn with the sun in the way, shouldnt cause a problem as jump space navigation cannot be proven to be linear, e.g the ship does not travel from origin to destination in a straight line, indeed there have been some missjumps that have resulted in no movement whatsoever or travel in a completly random direction. IMTU universe when the astrogator generates the jump plot, he or she gets an accurate fix on the present position before selecting a destination exit point in the target system. If as the result of an error, that exit point happens to be within the gravity well of their destination world, then a violent exit back into N-space results, this is different to violently exiting into normal space everytime a mass shadow protrudes into the jump universe, as after all this would make jump travel even more inherantly dangerous than it already is, after all there are billions of heavy objects in any straight line between this world and Barnard's star for example (a mere Jump 2 away). Given that the bulk of jump fuel is used up on entry to jump, one such precipitation would mean a long cold death amongst the stars in a stranded vessel.
My own take on jump space is that the ship doesn't move at all during jump(conservation of momentum etc), whilst the jump drive subtley interacts with the movement of the universe over time (as plotted via the tumble of the drive.) In other words at the moment of entry to jump the ship dissapears for a week, stays in exactly the same spot whilst the remaineder of the universe continues to move on and then re-enters normal space once again in the same spot (relative to the ship), but at a totally different location in space. Given that as per Newton's findings we expect the universe to keep on moving in the same direction, you might naturally ask, how could that same ship get back to its starting point as the motion of the universe has carried it even further away. Well friends this is where that crucial jump plot generated tumble comes in, IMTU tumble is simply a fluctuation of the jump field pregenerated by the Astrogations computer that allows subtle changes (milimeters) in the position of the ship in jump, hence giving it a small forward or negative velocity in terms of the rest of the universe and its plotted destination.
As 99.9% of movement would be relative to the ship, you could argue that the vessel stays still, its just the rest of the universe that moves. I understand that this is messey, but hell, so is jump physics in any case.
To illustrate the point, it is estimated that between every heartbeat we as passengers aboard planet Earth chained to the forward momentum of the solar system travel through a distance equivalent to the distance between the Earth and the Moon, and that's in under a second, can you imagine the awesome distances you could 'travel' by blinking out of this movement for a week....
Travellers within the jump field would be unaware of any of the events occuring in the normal universe, and would be effectively sealed in their own little bubble of relativity, Hence the trip could take months, years or decades relative to the outside universe, though to the travellers aboard would only feel like a week, should a mistake occuring during jump entry or plotting courses etc (hence the common staple of miss-jumps etc).
I also postulate that higher jump numbers such as Jump 3 to 6 etc, require more powerful drives capable of an even greater interaction with the dimension of time allowing greater distances to br traversed within that same 'relative week'.
Just thoughts but for the time being they satisfy me whilst retaining all cannon aspects of jump drives. When I get a minute I will submit a larger piece on this to the site.