From your description, the LCD is cracked. The outer glass you described is the touch screen digitizer and it sounds as though this is intact. If it was broken, even with the LCD visibly cracked, you would see that it was also broken. A similar question was asked in the forum titled, How do I replace a cracked screen?
In reviewing that post, the first answer indicates that the digitizer can be replaced independently from the LCD. Upon doing a search on Amazon for the LCD itself, I did find one listing that you could use to purchase it separately. However, the disassembly video in that post was focused on replacing the digitizer.
I found a similar video on Youtube, titled RCA 10" Screen Replacment - Disassembly - RCT6203W46 PRO, which may be more relevant to start from the back and work your way to the LCD. This video goes as far as replacing the digitizer, but you'll just need to remove the LCD and the respective connections and attach the appropriate ones to the new LCD.
Furthermore, I did a search on eBay and discovered that there are two versions of the LCD. One that is a straight lcd cable and the other that uses an l-shaped cable. It is important to purchase the correct one. This ebay listing is specifically for the straight cable, but the seller also sells the l-shaped cable as well.
How do you know which one your tablet has? You may need to disassemble it to find out, as there was no specific documentation that I came across based on the model number or manufacturing date that indicated a specific way to know. You could try contacting RCA support, but disassembling helps confirm it before you decide to order from eBay, Amazon or any other third party.