As previously mentioned, someone made cards to replace the dice.
The following cards are in his deck: (Ignoring "city" he added to every card)
- 6x Road, Plains, Hills
- 3x Road, Plains, Mountain
- 3x Road, River
- 3x River, Forest
- 3x River, Swamp
So it's safe to say the following represent the face of the dice:
- Road, Plains, Hills
- Road, Plains, Hills
- Road, Plains, Mountain
- Road, River
- River, Forest
- River, Swamp
So you were correct.
If these dice are all identical, they have the following faces:
+-----------+
| Ro |
| >|
| Ri |
+-----------+-----------+-----------+
| Hi | Mo | Ro ^ Pl |
| | Rd >| |
| Pl v Ro | Pl | Hi |
+-----------+-----------+-----------+
| Ri |
| >| Ro Road
| Fo | Ri River
+-----------+ Hi Hills
| Ri | Mo Mountain
|< | Fo Forest
| Sw | Sw Swamp
+-----------+
^
, v
, <
and >
denotes the top edge of the face. The icons are already correctly placed within the square. This indicates which way they should be facing. e.g. The Swamp will appear in the top-left corner of the face, while the Forest will appear in the bottom-right corner.