The Bible does not say that Isaac visited the king of the Philistines "in the days of Abraham", it says that he visited them at a time "beside...the days of Abraham", but the point still stands about the anachronism of Philistines in this time period. I think I already touched on this topic, but I can't find it, so I'll have to brave the possibility of repetition. The thing to remember is that when the Bible writers write about certain things, sometimes they're writing hundreds of years after the events, so they use terms that are anachronistic. There's a certain area of the Middle East that eventually comes to be known as the land of the Philistines, so if a person living in a time when Philistines lived in that area wrote about it, they might call those people Philistines even though the label was technically wrong, just because it makes it easier for the "contemporary" reader to understand. For instance, I might say that before Europeans came to the area where I grew up, the area was the territory of one of the most powerful Californian tribes, the Pomo. This is essentially correct even though the area would not be called "California" for hundreds of years after the Pomo were at the height of their power.
God "appears" to Isaac and tells him to stay in that land like his father. I already touched on the subject of God being "seen" in a previous post, but while not mentioned in the SAB I have to admit that it occurs to me at this point that I'm a little perplexed as to why God cares where exactly Isaac stays since he never gives him any land.
Now, Isaac goes to Gerar, and we largely see a replay of what happened to his father there. It's almost one of those things that a Bible critic might take as a mistakenly-placed story that only belonged in one of their lives and not the other, if not for the fact that the Bible actually admits that this is a similar story, but assures the reader it's a different one. This time, it doesn't go so far as someone taking Rebekah away from Isaac, but instead, the king catches Isaac and Rebekah making out in public. Isaac is not recorded to make any excuses like "Well, by 'sister' I meant 'cousin' really..." It's hard to say whether Rebekah was not as hot as Sarah, or Abimelech knew from what had happened last time (probably to his father) that this family was to be handled carefully, because God seems to like them despite their being pathological liars.
Many of the other issues in this chapter have been covered before, such as slavery, the naming of Beersheba, and polygamy, the last of which deserves the added note here that virtually nothing Esau does is set up as a good example.
This leaves only the issue of Bashemath's parentage. Honestly, there are a number of different ways that one could explain it away, but in the end, it's probably an actual error of some sort. It's a matter of personal taste whether or not a person wants to view the Bible as completely free of errors such as this one that really aren't of significance, or whether or not such errors are troubling. Did a scribe get it wrong, or did Esau have two wives with the same name? Or maybe there was another group of "Hittites" that were descended from Ishmael? As for me today, I'm tired and don't really care that much. Maybe I'll revisit it in chapter 36 if I feel ambitious a couple weeks from now.