While mapping with Offroad blocks, I found some more blocks which could be very useful:

Where the forest block 5-1-1 allows to make a junction in shape of a ┼ or a ┴, this is not possible with the block 5-3-1.
5-1-1
5-3-1
... because it gives this:
To achieve a junction, I have to use 5-1-1 and 4x 5-1-8

.
Not very dramatic, but sometimes a question of space left on the map.

The water jump block needs lot of space on water and it makes the car jumps very high.
It would be nice to have a similar jump but only 1/2 as steep that allows to cross a small river without the car going too far in the air.
5-2-10
For the replay I used hust two curves before and after the smallest possible jump distance.
I let the car start at the begin of the one curve, and already there it had so much speed that it nearly jumped over the road at the end.

blue trails are the car, green trail curve behavior kindly requested for a smaller jump

Blocks 5-2-4

and 5-2-7

have water outside, but not inside. It would be nice to have more possibilities for a road or path nearby the water, like to drive around a lake.
Actually one can only drive around an island:
