Part 1 (Masters, Experts and Novices)

TC1 at Hawkswood Fm (3729)
Via the following SHs, Brs and ETLs:
U    U    O    79    O    99    93    O    U    U    89    94    U    O    U    O    O    88
To TC2 at next GL.

Part 2 (Masters Only)

Continue via:
73    U    D    O    O    O    U    D    U    D    O    U    D    O    D    U    U    D    U    O    U    U    D
D    U    D    D    U    O    D    O    U    O    U    D    U    O    D    O    O    O    U    O    D    U    D
D    U    U    D    U
TC3 at last instruction.

Part 1
Unders and Overs with a few spot heights thrown in.
RC3 - Two solutions allowed, as the junction at Lane End in 3624 could just about be a staggered x-rds.
I consider the W arm of jn at 348.5 252 is an ntr, so this junction counts as a YYY.

Part 2
Unders and Overs as above, but with additional ups and downs of two types: 1.Changing class of road, e.g. w onto Y/O/G would be U, G onto O/Y/W would be D. 2.When you encountered a spot height, U if it was higher than the last one visited, D if it was lower.
Hopefully the inclusion of the first SH helped with type 2.
I can't see any clear alternative solutions from your answers, I am sure you will tell me if I have missed one.

RC7 - Rule 24 is quite clear about only counting your first visit to a letter. The 'C' in 3227 was the only dubious one.
RC9 - In 2722 you turn left from a G onto a Y, but this is not considered a junction since the Southern arm is an ntr. So ignoring this one, the next most Westerly is the GGRO in 2824.
RC10 - 3522 gives a shorter route than 3722, though it is perhaps "not as elegant", as Mr Towers pointed out.