I usually punt when the missus is otherwise engaged (work, out with friends, etc.) and find this works well. I don't tend to travel too far and punt for thirty minutes so I don't have a lot of time that needs explaining if she did call.
In terms of excuses, I do think you need a hobby that you actually partake in. smiths' is very good, but you'd need to actually play golf. The gym is good too, as is swimming, and they have the added benefit of showering before heading home. I'd be tempted to punt then pop to the pool for a few lengths, shower and home. The downside though is you probably only have one pool/gym local and you could be checked up on.
Finally, I used to have a great relationship with a pal when I lived elsewhere. I'd cover for him and he'd cover for me. We'd also do plenty together anyway. On occasion we'd meet for a beer, go our separate ways for the real agenda, and then reconvene later before heading home