after the chilterns/swinley you will find it rocky and it might sour your local riding.
despite what some say, dont cut corners, do the whole route, if you are gonna ride up the road… why travel all the way to wales to do that?
its a long way up and a long way back down, that said its a pretty short loop so just take your time first loop, grab some lunch, and you know what you are in for on the second lap so you will enjoy it a bit more
EDIT: if you have pads that you ride in, no harm in taking them, if you take them, wear them, dont leave them in the car!