Let's go through the Championship one by one (generally North to South (ish!):
Edinburgh - off the second bend, away from the crowd.
Glasgow - off the second bend towards the back straight, up on high, visible to most, if not all the crowd.
Berwick - off the the fourth bend, easily seen from back straight and maybe a little from the main stand.
Newcastle - off the first turn and anyone can stand next to the fence and look in the pits during meetings.
Redcar - Apex of turns 3 & 4 and everyone can see from the crowd
Workington - entrance to turn 1 and you can easily look down from turn 1 and see into them
Scunthorpe - off turn three and not easily seen (especially the away pit as it backs on to the home pit.
Sheffield - off turn 4 and you can stand next to the pits in the main stand on the home straight and also from the stand on 3&4.
Peterborough - off turn 2 and easily seen from the main stand and also if you stand near the pits.
Ipswich - just before turn 1 and not easily seen into
Lakeside - (at Rye House) entrance to turn 1 and can be seen if you look down off turn 1 but not easily if you are in the main stand or further along towards turn 2.
So (at least in the Championship) generally the pits can be seen.