I'm Canadian and I always buy US travellers cheques. I also take about $500 US cash with me, just to get me started. You really don't need to have that much cash on you at the outset. I just don't like having to get a cheque changed for the first few days.
As a Canadian, it can be a bit confusing because you might try to keep converting mentally. For example, if you buy a drink for $3.50 U.S. and give a $5 US bill, you'll probably get back $$1.00 US and $1.00 BZ. So you'll be thinking to yourself that your drink was worth $5.11 Canadian and the change doesn't seem right and that's worth . . um, er . . . $2.19 Cdn . . .and um, er . . .I didn't tip yet . . .and um . .
Save yourself the calculations. Just figure out what your budget is approximately per day. Review it every few days to see how you are doing. Think in US dollars or BZ dollars, don't try to convert mentally to Cdn. Until you are used to it, you might go crazy unless you remain perfectly sober at all times and are a really good with numbers. All you need to know is how much you plan on spending over all, how you are doing with that and that the BZ dollar is set to the US dollar 2 BZ = 1 US.