Are you familiar with the texts used by Canadian public schools? They might be worth a look. While I wait for CLE’s upcoming 11th-grade US history text I’ve been happily using one of the common secular texts published by Glencoe/McGraw-Hill. It’s about as neutral as possible towards religions and ideologies. I strongly prefer it to the US history texts from ABeka and Bob Jones. Its main drawback is that it is HUGE; they crammed every possible thing into it so that no one in the entire United States could accuse them of leaving something out. I have to aggressively skip chapters and parts of chapters to make sure the basics are covered.
A brief search didn’t reveal much to me about secular Canadian history texts, but there’s one called Canada: A Nation Unfolding that you can get pretty cheap on eBay if you’d like to check it out.