彼の話はばかばかしいと言ってもいいくらいだった。
His speech verged on the ridiculous.

I've been trying to find some more complicated examples in the net. Here is one of them. It shows くらいだ can also be preceded by a phrase.

The usage of くらいだ／ぐらいだ　with the meaning of So A, to the extent A
Shows the extent or degree of something (which usually precedes this expression) seems to be too complicated for N5. At the top of that section is says that it is N2, so I am not sure why it shows up in the N5 grammar section. When I read through examples of how it has been used by others, I get confused.

For example:
病院にいったぐらい、走り過ぎた。
I ran so much that I went to the hospital.

I would have thought that it would need to be:
走り過ぎるぐらい、病院にいった。

Also, does the だ need to come straight after the くらい?

I would really appreciate some more help on this grammar.

I'm not too sure how to answer the だ question. だ is the informal copula of です so it really just depends on the situation. I would generally just leave だ off completely in speech or emails if くらい happened to be at the end of my sentence unless I was really stressing something and then would probably use だよ.

The example sentence for the second meaning is using the 漢字 for くらい. Is this natural? So far, I've only seen 「位」 used when it indicates a counter word.

I don't think grammar point [b]1 of 3[/b] is explained well enough here, I'm having a really hard time grasping how this works and I've almost finished working my way through everything in JLPT5 and the related grammar like this one. The only examples I can see that actually end with くらいだ are ones that say ～ても〇〇くらいだ, otherwise the くらい is in the middle of the sentence and seems unrelated to this point... and I'm still not even sure how the ～ても〇〇くらいだ thing works...