I would not try to discourage most people from entering this business if they have a good business plan and the will to try; however, in this case with a leased/rental truck with no sleeper and, seemingly, failure to do enough research on your own without full knowledge of DOT and IRS regs plus legal and accountant guidance, I think you are setting yourself up for failure in a short amount of time. With the limited info provided, we cannot tell if you are getting $2.10 a mile or 70/75% of $2.10 a mile. Without a sleeper in the truck, your co-driver is essentially useless for the purpose of extending drive time so you may as well drive solo and avoid your daily $135 expense. If you company wants a 26 foot box, they will want 26 feet of cargo space, so forget a box sleeper. On the east coast, you'll be lucky to average 500 miles a day. How much of that is deadhead back home and will you get DH pay? You'll need time off for for truck PM and CM, that needs to be considered as part of your time.
My fuzzy math sez you'll have weekly expenses of $525, rental, 440, mileage; 675, helper; 675, self; 400 motels; 1500 fuel; and 250, tolls. (Total est thus far $4465) You still have rental vehicle, liability and cargo insurance costs, OTR food costs and any charge-back costs that the carrier my impose such as ELD installation and rental fees. You'll need adequate FMCSA approved load securement devices and truck fittings. It's hard to tell if you are investing in a business or just buying a job for you and your friend. Good luck on your choices; we truly wish you success in expediting