4 x 4 feet? How did you reach all of the ares you needed to work on? Did you lay it down or stand it upright? The largest drawing I've ever done was a life size portrait of Aaron, wearing the Breastplate of Judgement. It was from his upper thighs to well above his head and I drew it while it was lying on the kitchen table....my back hurt for weeks afterward!
Seeing artwork is always better in reality. I had the opportunity to go to Paris a number of years ago and was able to see my favorite sculpture in the Lourve....Canova's Cupid and Psyche. I was entranced at it's beauty and spent three hours just looking at it from different angles. Interacting with the actual piece of art, any art, is the best!
All my works, no matter what size (I did a painting that was 8X6 ft) and done on a drafting table. I break the work up piece by piece before putting them together. I need to, since I have a back injury from my mountain days, and putting too much stress will be murder on me.
I was able to see most of the great masterpieces in the USA, especially at the Smithsonian. Aside from art, there was everything to absorb, from the Aero-Space Museum, to the other Library of Congress. What blew me away the most was a special exhibit on Art Nouveau which was one of my great inspirations as a child. I was dating someone there, but I nearly neglected her, when I took her to the museum.
Well as for our backs, that's our bodies telling us of our age and to take it easy but not be idle. Or were we just reckless when we were younger and paying for it? I am partially doing that.
I was last in the USA in 2000. I first spend about a decade roaming around my country and living with various ethnic communities. Then when I went to the Smithsonian, I saw that I have seen enough to saw that I can truly teach art. I am still seeing art everyday, that was just the catalyst to say I'm ready for teaching (especially art history). Indeed it was a blessing.
A future blessing would be to meet you and to gaze into your works face-to-face and not interface-to-interface.