Late to the discussion but I would recommend that you take the time to learn how to use a DAW. It's really not all that difficult. Certainly much easier than trying to convert files designed to work with a particular synth, into a file that can be read by another different program that uses a different file format.

You can still get Cakewalk for free and there are probably a few others that are free if it's only a "lite" version. If you are on a windows machine, and if you have Band in a Box, you have Real Band which is a rudimentary/basic DAW. I prefer Cakewalk. I'd think that you would get better sounding results using the synths designed to play the samples as opposed to trying to convert them into a different platform. The simple reason is that many of the samples in the better sounding libraries and even the cheaper ones are multi-layered samples. I'd imagine that soundfonts are mostly single layer. I used to use them and thought they were a great step up from using general midi. However,, while a step up from GM, they are certainly no match for the quality of today's most basic sample players and synths. Your player for the fonts isn't even capable of properly using the layered samples. We're talking about the overall quality of the sounds you're going to be hearing.

When you decide to take the step, there's a lot of knowledgeable folks here to call on for assistance.

You can find my music at:
www.herbhartley.com
Add nothing that adds nothing to the music.
You can make excuses or you can make progress but not both.

The magic you are looking for is in the work you are avoiding.