I can understand and appreciate that. Just let me know when / if you want to do the complete loop. The back half is a good 3, maybe 3.5 in the dry riverbed. If it has alot of water, I would put it at 3.5 easy. I don't know if I would do it with the big boulders under water.
Once you get past the dry river bed the shelf part of the trail is washed out and rutted in many areas. Lockers would be a benifit but if you have enough movement in the axles you should be ok.
Scott