I personally did not experience as much intrusion as some other ones have. Although I think that is partly because the most nosy elder moved to another congregation but I know one of my good now apostate friend had his life made hell by the same elder.
In my case I was mostly bombarded with snarky comments and remarks. Like this elder, which is the one I converted with, would call me on a Saturday to have me fix his computer. I would show up with a half grown beard and then he would ask "how was field service this morning?"
My good apostate friend was in a band that played at most JW parties. Obviously their songs were mostly innocent but some of them could be interpreted with double meaning. He has had elders encourage people to leave the party because he would refuse to quit playing those songs. After being DFd, he had to cancel contracts (even when he accepted to not play, just provide the equipment and the rest of the band would do it). He has had to cancel contracts on the eve of weddings because of this.