Note that RPR considers club to be the 6th and 7th floor now. The Club Lounge and Staff are on the 7th floor, but you can be assigned to club on the 6th floor. (We booked Club and were assigned the 6th floor, which we were not at all happy about.) They did this due to RPR Club's popularity. You can asked to get comped club access, but I would think it would depend on how busy the hotel is, and if the 6th and 7th floors were already full. The lounge can be crowded during busy seasons/peak breakfast and snack times.
The rate to upgrade at check in will depend on the rate at which you booked. When we were Gold, we spent $100 extra per night for club because we booked at the AP rate, and we already had a water view room booked.