What would be an acceptable method for wiring holiday lights for year round use?

The downtown area organization wants to have the lights year round but the wiring is single insulated conductors taped from lamp post to lamp post and then a plug attachment for the light to to plug into. Some of the runs have plug attachments taped together in the middle of a span.

Besides for the spans being over ten feet and the single conductors not being on insulators and the installation being installed for over 90 days it looks great. The power is originally picked up from a built-in receptacle located near the top of a street lamp post.

What would be an acceptable permanent setup?

Using some type of sunlight resistant cord or cable, installing a tension wire and mounting receptacles with weather-proof while in use covers to the posts or trees? Are any Christmas lights allowed for permanent installation? Does a disconnect have to be readily accessible? accessible? Or is it ok to use a ladder to reach the receptacle mounted about 12 feet above grade?

Is it ever ok to have a plug, male to female in the middle of a tension span? They are taped up pretty well.

Is GFCI protection required for this type of installation?

Any input would be appreciated.