If you want to be discrete then its bets to park on a meter in the street nearby because otherwise you have to pay for parking at recpetion.
There is no side entracnce - but dont stress, peopel go in and out of hotels all the time.
As you walk in the reception desk is ahead and then the lifts are to the left and the bar is further left of the lifts. The loo is down a corridor between then lifts and reception.
So if youre nervous - go in and go to the bar, get a coffee - its allowed - and the bar staff will not knwo youve coem to fuck a hottie!! Thre walk to the loo and when you come out just get in the lift.
Personally I woudl park in the hotel car park and just go to the lift and see the girl and then pay at recpetion for parkign on the way out - simples!