I ran 100amp to my detached garage a few years ago. #1 aluminum NM in the basement stapled to the floor joists, splice using Panduit splicers inside of a large junction box to #3 copper THHN. 2" LB's and PVC. PVC from the junction box to LB fitting, PVC underground 18" to other LB, PVC to electrical box in garage. Unbond ground and neutral in garage electrical box. Pound in 8' grounding rod, #6 copper to garage electrical box. Used a pull string and wire pulling lubricant, no problems with 2" PVC.