If you drive Nema-Bassikounou- Fassala Nere (Mori border)-Nampala-Lere(Mali border)-Goundfam- TBT, you don't need WPT. THere3 is a clear and easy piste an no problem on the border.
I did drect piste Bassikonou- Lerneb(Mali border)- Goundam last winter without WPT. Quite tricky to find way somethimes and som confusion on border. Formalities in TBT. In fact the piste is not a straight one, but from vilage to vilage or from well to well.
There is also a piste Nema-Lerneb, which join our one.
WPT: N 16.38,286 W 007,11.530
N 16.46.785 W 006.41.125
N 16.51.242 W 006.07.470
N 16.49.435 W 005.54.715
N 16.53.395 W 005.39.015
N 16.54.210 W 005.39.015 border
I don't know where is a mori police there. Probablly nowhere, but if you don't have really great experience and don' want to have a problems I sugest the first option