It'a bit weird around Dorking. Are you purposefully seeking out Leith Hill? You could head south to Newdigate, then across to Capel, Ockley and back to Forest Green without going over the highest hill in the south east.
I'd also hang a left in West Meon and nip down to Warnford, then head up Wheely Down and into Winchester that way. You'd be on the A272 for a bit, but it's downhill and much less contrived than heading up to Alresford and in that way.
It'a bit weird around Dorking. Are you purposefully seeking out Leith Hill? You could head south to Newdigate, then across to Capel, Ockley and back to Forest Green without going over the highest hill in the south east.
I'd also hang a left in West Meon and nip down to Warnford, then head up Wheely Down and into Winchester that way. You'd be on the A272 for a bit, but it's downhill and much less contrived than heading up to Alresford and in that way.