I want to know how the''T. Ginideach'' is used with words like ''a lán'', ''go leor'' and ''roinnt''.

I understand that it is used in the following context:

1)Tá a lán oibre déanta agam, tá go leor airgid agam.

I trust these examples are correct.
Is the T.G. always used with these words?
2)Also, if I want to use it with a noun something like ''campsite'' - ''láithreán campála'', would I say:

Tá go leor láithreáin campála thart timpeall/tá a lán láithreáin campála thart timpeall?
In other words, is this the T.G. or is it simply the plural?

4)Lastly, does ''roinnt'' take the T.G.? Can you give other words that need the T.G. also?
5)I know verbs can change words e.g. ag insint scéil, ag crú an mbó(?), ag insint bréag(?) etc. Is this the T.G.
Apologies for the muliti-faceted question.
Go raibh maith agaibh

Yes, it is.

Genitve plural: go leor láithreán campála

It depends on the version of Irish. Usage of genitive plural is Standard Irish.
But probably many native speakers wouldn’t use genitive plural.

All nouns - except a few, e.g. cúpla.
And there are rules and situations genitive case forms are not used.

Yes.
But insint, crú aren’t verbs but verbal nouns.