I used the Amoy Bible a lot when I was first learning Hoklo. It turned out that there were big differences in the Hoklo in the Amoy Bible vs the Hoklo spoken in 21st century TW. A few yrs ago, though, I spoke to a lady who'd immigrated to TW from Amoy as a kid, then mostly hung around Mandophones -- meaning that her Hoklo didn't really keep pace with the times, nor Taiwanize. I was amazed at how easily and completely I could understand her. It made me realize that I hadn't been as bad at learning Hoklo as I'd thought. It's just that my learning materials had been out of step with the language.
The 紅皮聖経, published in the 1970s and immediately banned by the Chiangs, can be found on the 信望愛 FHL website. Hands down the best choice for learning Taiwan Hoklo. Not sure, but it may
actually be closer to modern M'sia/China Hoklo than the old Amoy Bible.
One of my favorite writers in any language is 陳雷 Tân Lûi. I have w/ me a collection of his short stories entitled 無情城市. His "great work" is 鄉史補記, which would be a famous book if he would've "sold out" and written it in Mandarin. Historical fiction. A work of staggering imagination. 台湾个店 is the best place I know of to buy his stuff. The FHL website also carries some of his stories.
I've heard that some Hoklo professors in TW assign a book by 蔡培火, published in the 1930s and written in romanized script. It's also online now. He was an official under the Japanese and the book is mostly about public policy and the future. His dialect is very different from modern Mainstream TWnese and some of his usages are things I would associate with M'sia/Sg today. I can post a link if anyone needs it.
On a different thread, you bring up something about the non-standardization of kanji, etc. I strongly recommend using the 台日大 (http://taigi.fhl.net/dict/) and the 台語白話小詞典--must buy at 台湾个店 or www.atsiu.com. These two dictionaries are both meticulously accurate. They don't assign a kanji unless it's either etymologically established or "socially proofed".
The 台華綫頂 is useful b/c it's so flexible and comprehensive, but it can be inaccurate and its definitions have no depth -- it's just a big wordlist. The 台閩常用 is useful too, but they "force" every Hoklo element to have a kanji, and their methods are somewhat Sino- and Mando-centric. They aren't as "realist" as the 白話小詞典. I use all four dictionaries together. Other foreros swear by Douglas and Campbell as well. Apparently a new dictionary will be coming out for Penang Hokkien.