Yes.
Photos is easy, in places you're as close to the track as at the likes of Knockhill
Hope the link works
https://1drv.ms/u/s!AlB7bV6RdTovowIHmh4K0fHkHnBv?e=36VXnRYou can split the track into 4 sections for access
The main race track area Ford Chicane to Tertre Rouge is all walkable - unsurprisingly this is the Bugatti circuit plus the esses to TR.
Mulssane Corner, you can get a bus down there and back
Indy/Arnage you can get a bus down there and back
Porsche Curves, you can get a bus down there and back too
I believe it is possible to oeek through on the Hunaudieres but you're not going to see much!
What me and dad did was spent most of the first day at the main section and the museum, then got the bus to mulsanne around sundown, moving round clockwise, so indy and arnage in the dark (just in time for a safety car...) then onto the porsche curves and back up to the grandstand.
Dad went to sleep... I went for a wander around the back of the pits and various displays then around the area in the dark including the terracing below the stands.
General Admission is pretty cheap, but the grandstands can cost you, so look at the map carefully
Think we were in Bernatto Tribute 14 which was a pretty decent spot as could see up the track to the bridge and down to the podium, missed the ceremonial start and then it was a safety car start for the race itself cos of the rain.
The stands were only full for the start, but not sure if you can sneak into the others through the night.
Once the race is over the track is unlocked and you can either leg it down to under the podium or use it as an easier walk back to the tram
Something else to be aware of, the tram drops you off at Tertre Rouge and you use the entrance for the far corner of the bugatti circuit (where the busses to the rest of the track leave from anyway)