Use postcode DG1 1QB to reach Ae forest, then follow signs for the trail head. 

The OS Grid Reference for Ae trail head is: NX982901.

From Dumfries
Take the A701 towards Moffat and the A74(M).  After about 10km, look for signs to Ae village.  Take the left turn off the A701 to the village.  Go through the village (about 4 km from the turn off) and turn right into the Forestry Commission area.  The 7stanes car park is signposted.  Go past the Forestry buildings turn left onto the minor road.  The car park is 500m further along.

From Glasgow
Follow the M74 south to junction 15 (Beattock) and join the A701 towards Dumfries.  After 19km look for the second turn off for Ae village on the right. Take the right turn off the A701 to the village.  Go through the village (about 4 km from the turn off) and turn right into the Forestry Commission area.  The 7stanes car park is signposted.  Go past the Forestry buildings turn left onto the minor road.  The car park is 500m further along.

From Edinburgh
Follow the A702 south through Biggar to join the M74 at junction 13 (Abington) and then continue on to junction 15 (Beattock) and turn off onto the A701 towards Dumfries.  After 19km look for the second turn off for Ae village on the right. Take the right turn off the A701 to the village.  Go through the village (about 4 km from the turn off) and turn right into the Forestry Commission area.  The 7stanes car park is signposted.  Go past the Forestry buildings turn left onto the minor road.  The car park is 500m further along.

From Carlisle
Follow the A74 north.  There are options at Gretna to take the A75 to Dumfries and then on to the A701, however, continuing north to junction 16 (Annandale Water services) of the A74(M) then heading via Johnstonebridge and minor roads to join the A701 at St Ann’s is slightly shorter.  At St Ann’s, turn left onto the A701 towards Dumfries and continue for 9.5km to the  second turn off for Ae village.  Take the right turn off the A701 to the village.  Go through the village (about 4 km from the turn off) and turn right into the Forestry Commission area.  The 7stanes car park is signposted.  Go past the Forestry buildings turn left onto the minor road.  The car park is 500m further along.

From Stranraer
Take the A75 east to Dumfries, then join the A701 towards Moffat and the A74(M).  After about 10km, look for signs to Ae village.  Take the left turn off the A701 to the village.  Go through the village (about 4 km from the turn off) and turn right into the Forestry Commission area.  The 7stanes car park is signposted.  Go past the Forestry buildings turn left onto the minor road.  The car park is 500m further along.

Disclaimer
These are suggested routes only, using the most direct routes available.

Cheers.

Si..