I use 4 of those yellow plastic chocks. Works fine for me but I'm too cheap to invest in the big rubber ones.
For the tongue jack, I've done what you have but I would be more comfortable with a larger footprint for the blocking under it at least for the bottom portion. The previous owner of our Roo gave me a tree stump cut just right for that purpose and I kept it when we sold the Roo. You could just cut a 2x10 into 10" pieces and stack and screw them together to give you the height you need.
When I parked the Roo in our driveway I had to use a 2 step process to get the tongue high enough to level it. I first raised the tongue with the jack to near its limit and then temporarily rested the A frame on some axle stands that I placed on blocking. Then I placed the 14" high stump under the tongue jack with a 6x6 on top of the stump and lifted it to where it needed to be. It would work without the extra 6x6 but the 6x6 allowed me to avoid stretching the jack too high which made it more stable.
2011 Rockwood Signature Ultra Lite 8293SS, 12K Equal-i-zer
2016 Ford F-250 XLT SuperCrew, 6.2L, 4x4, 6'9" bed, 3.73
2010 Rockwood Roo 23SS (2012 - 2014)
2009 Ford F-150 XLT SuperCrew, 5.4L, 4x4, 5'6" bed (2012 - 2016)