So last month I was on holiday in the UK and I went to Lyme Park (where the 1995 version of Pemberly is) because *gestures wildly* Pemberley.
What was interesting though is that the "front" we see in the BBC series is actually the back of the house. The original is a hunting lodge from the 14th century (from memory) that had extensions added over the years.
(Apologies in advance for the quality of the photos, they were taken on a digital camera for vibe reasons)
This is the actual front of Pemberly, most of which is a hodge-podge of older buildings (done by major renovations in the Tudor and Jacobite periods), but with Georgian windows and a facade added in because that's just what the Georgians did.
Well the back is as seen in the mini series, lake included, but the interesting thing is landscaping. It's a little difficult to see, but on the right, there's terracing along to the orangery/greenhouse(??) and the rose garden, before the path splits and wraps around the lake to where I took these pictures (and got terribly bitten by midges, which I'm apparently allergic to).
You can just about see it in this picture in the bottom left.
Unfortunately I didn't get a lot of pictures of this part because someone was taking their wedding photos and I didn't want to intrude.
My point is, Lizzy's carriage could not have gone this way -- it is impossible to enter the house via carriage in this direction.
So what about the other way around? There's certainly the path for it. Look at this lovely avenue of trees that form a front drive!!
Except it sort of goes into this as it continues around, and is fenced off as it becomes a sort of kitchen garden type thing full of herbs, before going down hill.
Okay, so they can just go down (into what is now the carpark) and then curl around that way and back to the front.
Terrible photo, but good luck mate. The walls are probably between 5m and 10m high here. No one is getting up there, even climbing. The only way up is that little path running along the garden, which is:
Incredibly steep, like walking backwards steep, and;
Is actually pretty far away from the house and takes you to a neighboring field-walk
Resorting to google maps (by this point the midges have killed me and I'm itching like mad), you can see that grove of trees at the bottom of the aerial, don't link up to the path round the bottom. There's actually a metal fence in between them, but lets say it does link up and you can get through that way.
Our second problem is less easy to try and find a work around for. The path at this point is far too thin -- it's basically a walking path (with midges, yay) -- twisting and steep to get any sort of carriage along there. The path then narrows to a small bridge which goes across that little steam (because the lake trickles downhill into another lake near the cafe, which is in a building where a farm used to be).
It would be doubly impossible to get anything through this small pass and and onto the path that runs along the (right-hand side of) wall here.
And then to cap it all off, there's more stairs, both at the circle, and at the slim arches here. (You can just about see it in the photo too).
Basically, the cinematography was amazing enough that they tricked us all. I was talking to my dad about it (who gets very nerdy over films and TV shows and loves P&P 1995) and we reached the conclusion that they used a combination of trick filming and perspectives to make it seem like Lizzy's carriage could make it past the lake and around to the "front" of the house, when instead they probably either lifted the carriage or constructed it in situ.
TL/DR: The front of Pemberly is not the actual front. Various angles and cinematography tricks were used and they probably carried/assembled the carriage in situ since there is no way to get to the "front" otherwise.