I worked in Saudi for nearly 3 years, I lived in Bahrain and commuted over the causeway every day. I have little experience of Riyad, I have worked mostly in Dammam and Al Khobar and less so over in Medina and in the interior on and off over the years. I had a well paid job and had to get back to UK be honest, the money to my mind never really compensated for the lack of things to do, socialising (in Bahrain) was ok and relatively unrestricted, clearly in Saudi its a no alchohol state and there are few cinemas, and so eating out is the only social event outside of western clubs and secure areas. You can go dune bashing which is a hoot, although I broke my spine (I have recovered) doing that so be careful. The weather for most of the year is pretty unbearable, and you need to stay indoors , or keep outdoor activities to short bursts, with a shower at the end of them. From about April through October it will be over 40C and I have measured 52C at the office I was working in Dammam, I think the highest temperature I have ever seen out there was just over 60 and yes its too hot to do much really, you tend to stick where there is air conditioning. Winter weather is nice, day time it can drop into the mid 20's and its pretty nice. but don't expect gorgeous beaches they have a different attitude to sand than we do.
you will be able to send sunny selfies home and pictures of pool side parties with blazing sun, buy or rent fast cars, and it will be and adventure for a while and might be a good experience, but I know few people who given the choice would opt to stay out there.
Don't know if this rambling helps but for what its worth I would not do it again.