I left my pup when he was about 4 months for 5-6 weeks. There was no other way around the trip it was a family emergency. Luckily, my best friend was able to live in my apartment during that time and took care of my pup.
The only thing I noticed when I came back was other than he was HUGE compared to when I left him, was that he started lunging at people when we walk. My best friend told me it had started a couple weeks prior to me coming back. He was excellent with my dog but when he moved out, and my dog had developed this trait, I had to deal with it myself.
I saw no change in his behaviour other than that. He's always been very watchful of me, protective and a velcro dog. He always believed I'd come back for him, so that really eased out his separation anxiety.
I think the thing that really helped was the fact that my best friend had been introduced multiple times with my dog beforehand, and the fact that my best friend moved into MY apartment. So there was no environment smell. The apartment was still his den, the smells were all familiar, and the apartment undoubtedly smelt like me. I believe that really helped him adjust to me leaving.
So if you can have the caretaker (ie. My best friend) to live in your house, I strongly believe that would help.
To me personally from my side, it wasn't easy leaving him. I kept thinking of him and I felt almost incomplete because now me and my dog have become a package, if you know what I mean. Make sure when you leave your dog, you'd always have access of knowing how he is.