Concur with the above -- to do seatbelts properly (so they do their jobs when the time comes), you *are* going to be drilling holes. So get over that and get to it.

The first one is the hardest -- they get easier after that. I did my seatbelt upgrade not too long after my first grandchild was born. I figured it was going to be a requirement sooner or later ... (either from Mom or Nanna ...

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I went the lap and shoulder belt route. Got the kit from Juliano's. Their instructions and diagrams were outstanding and I did the install in about 2 hours. It was nearly easy (getting the backing plate in behind from the should mount was the challenging part but doable). The smaller hands you have, the easier it is.
I didn't need to remove the gas tank for the buckle end attachments -- they just went in the floor at the back of the seat riser.
I got the red belts and they look right at home in the truck.