HI
first off, I speak of the USA only. NO , nav aids are not turned off at night to save power. We utilize our airports 24 hours a day (noise restrictions aside...but the ILS is still on).
Second off, utilizing an instrument approach (of any kind) at one airport and then proceeding visually to another airport is just fine as long as you coordinate it. It is not marginal as long as you are in compliance with existing regulations. And that you are competent.
Now, what to do ? IS the airport you intend to go to without an instrument approach? IS the wx reported / forecast to be at or above basic VFR (VMC)?
YOU can ask for radar vectors at the minimum vectoring altitude OVER the airport you intend to land at, and if YOU can proceed VFR, advise ATC of cancellation, or request a visual approach and go to the airport and land.
But lets say the ceiling is solid (undercast complete) and you cannot see the airport, but it is reporting 1500 OVERCAST and 3 miles visibility. And so is the airport 20 miles away and it has an ILS. Fly the ILS and ONCE YOU ARE VMC/VFR , cancel the IFR and proceed (with other clearance depending on airspace) to your intended airport.
Even more and niftier things can be done if you properly coordinate and receive clearance for an ILS, and then get a SPECIAL VFR clearance and then proceed in basic vfr out of one airport to the other.
NOW, I don't want to tell you what to do, because if you have to ask on PPRUNE, you probably need some more flying lessons.
So, be careful and maybe find a really good flight instructor/instrument instructor...you know, someone with a couple of thousand hours and have him teach you. And then pay him well because he has to earn a living too.