Get what you want. If insurance $ is an issue, go cut a few more yards to afford it. I'm not being an a-hole, I am telling you what I tell my sons, and what my father told me. It will serve you well to have the mindset of "If I want it, I am going to go get it."
A little something I have learned in my 33 years....If I want something, truly want it, I will figure a way of getting it. I always have, and always do.
The 300 seems like a fine engine. You are right, it doesn't sound that great. All straight six engine share that blahhhhh sound. Its just not a v8. You can make a 302 or any other v8 have plenty of torque for towing. The 300, or any other straight six is not a holy grail of torque. Its all in gearing, and torque curves. The 300 just happens to have a lot of torque in the lower rpm range where v8 usually don't.
1988 F250 Supercab Longbed 7.3 IDI, C6, 1356, GEARVENDORS, 4.10 Sterling with autolocker
1986 F150 302, C6, 9" 2.75, Wood Flatbed