I would suggest checking to see if you can rotate the toilet in its current location--It may be less hassle and expense than you think, and makes the room more functional. Then you could have a 4 feet wide x 2 feet deep vanity cabinet that would provide for plenty of storage for guest towels and supplies. Then as suggested, remove the header above the shower door opening and install a frameless shower door (Or you could use a shower curtain). Toilet paper dispenser in the wall where toilet is currently (or on the side of the vanity cabinet, where it would not be visible from the door). Towel rod for the vanity could be on the same wall as the entry door, to the right of the sink.