Just down the road from Hermonville in the village of Merfy (south on the D530 then at Trigny, turn left onto the D26) is the excellent Chartogne Taillet.
Head further south (on D26) towards Gueux, where the elusive but mythical Jerome Prevost is based. There is also the remains of an old Grand Prix motor racing Circuit de Reims-Gueux. Head west (turn right onto the D27) to Janvry where there is a reasonable house - Lamblot.
You can then head back to Gueux and south again (right onto the D26) to Vrigny where there is Roger Coulon and Lelarge Pugeot.
Head south once more (D26) to Jouy-les-Reims where there is a very interesting house - Aubry; who use some of the forgotten grape varieties. There is also Francis Cossy.
Keep heading south (D26) and you come to Ecueil where there are a couple of good little houses. Lacourte-Guillemart who we visited last month and then Maillart.
Keep on the D26 and after Chamery you come to the main road between Reims and Epernay (D951). Turn left towards Reims and then first right takes you onto some really good villages on the Montagne de Reims.
After Villers-Allerand, you come to Rilly-la-Montagne where the excellent Vilmart are based. Also in the village is a nice little grower-producer - Hubert Paulet and a good little negociant - Andre Delaunois.
The next village is Chigny-les-Roses where Cattier, a reasonable sized negociant is based. There are also a couple of very good grower-producers in J. Dumangin and also J. Lassalle.
Hopefully that will give you a bit to go on.
Alternatively, if you don't mind do a little bit of driving in one hit, you could spend the day going from one excellent house to another in one of the top villages such as Ambonnay or Bouzy.