Yes, God does freely offer salvation to all and yes, it is Reformed to say that. Here's a link to my digest of John Murray's article "The Free Offer of the Gospel" and here's a link to Mark Horne's defense of that article.
Just commenting on your book list - Graeme Goldsworthy is a former lecturer at my Bible college here in Sydney, Australia (Moore Theological College) and just wanted to say how pleased I am that you are recommending his book! :) He's a terribly lovely lovely man!
"What has a man from all the toil and striving of heart with which he toils beneath the sun? For all his days are full of sorrow, and his work is a vexation...There is nothing better for a person than that he should eat and drink and find enjoyment in his toil. This also, I saw, is from the hand of God, for apart from him who can eat or who can have enjoyment?" (Ecclesiastes 2:22-25)