In my travels around the country, the question I hear most frequently is: "What is going to happen to interest rates?" It's a good question, probably the most important one concerning the economic outlook for 1985 and beyond.

The first point to make is that interest rates have already declined significantly from the peaks set about the end of May -- more so and faster than experts such as Henry Kaufman of Salomon Brothers and housing expert Michael Sumichrast had expected.

"I'd be lying if I told you anything different," says Sumichrast, chief economist for the National Association of Home Builders.

On the long-term side, U.S. Treasury bonds, which paid around 13.75 percent at the end of May, now yield only 11.5 to 11.75 percent.

Mortgage interest rates -- the critical key to the helth of the home-building industry -- are also down, but not as much: fixed-rate, 30-year mortgages have dropped from 14.75 percent to 13.25 percent, and the popular adjustable-rate mortgages have declined from 12 percent (for the first year of annually adjustable mortgages with a "cap") to about 11.5 percent.

In the short-term market, 91-day Treasury bills, which topped 10.5 percent in June, and again in August, are down to the 8.6 to 8.7 percent range.

These are still very high rates by historical measures (especially in terms of deflated or "real" rates). Thus, the operative question is whether -- in response to Federal Reserve Board influence and the normal operation of the marketplace -- interest rates will go lower or the decline is about over.

There are two basic schools of thought about this, and the more candid practitioners in each will tell you up front that predicting interest rates is something of a crapshoot.

The first school thinks that there will be a further drop of a half-point to one full point in mortgage rates to bring them into line with reductions in other interest charges. Except for that, this group thinks that the overall interest-rate decline has gone as far as it will go. They believe that these lower rates will stimulate economic expansion, and quickly bring about higher interest rates in 1985.

But the opposing school of thought is that interest rates need to, and will, come down substantially more, because the economy is heading into a recession -- perhaps a steep one. They feel the Fed will combat this trend by a further and more aggressive dose of easier money. The most recently published minutes of a Fed board meeting -- for Oct. 2 -- show that the seven governors were split almost evenly on which course to follow.

The big unknown is whether the Reagan administration and the Democratic congressional leadership will deal with the huge budget deficit: so long as the red ink continues to flow heavily, the Fed is certain to be somewhat inhibited in loosening up monetary policy, for fear of setting off a new burst of inflation and a sharp decline in the foreign-exchange value of the dollar.

Kaufman thinks that the talk of an early recession that will bring interest rates cascading down is off the mark. He said in an interview that housing will enjoy a good recovery in response to lower mortgage rates. He points also to "a substantial volume of auto production" being scheduled for the first quarter of 1985, as well as higher estimates for new factory expansion planned by business. All in all, Kaufman sees a resumption of moderate economic growth in 1985, reviving business demand for loans. Hence, higher interest rates.

On the other hand, New York analyst Sam Nakagama says that despite the sharp drop in interest rates to date, "this does not mean the Fed's job has been done. . . . The recent level is extremely onerous to business firms at a time when the rate of (wholesale) inflation is zero and productivity gains have vanished."

The best scenario would be a further gradual decline in interest rates, stimulating housing and other interest-sensitive sectors of the economy. It would also encourage a further and gentle dip in the overvalued dollar -- now down about 10 percent from peaks of two months ago -- and perhaps restore some of the jobs lost as the U.S. trade deficit soared.

And for Third World countries, a decline in interest rates would be an enormous tonic, since much of their debt is on a floating-rate basis: a 1 percent decline would cut the Latin American debt service by as much as $2 billion to $3 billion a year, according to international experts.

But it will take some time to determine whether things work out this way. More than a little depends on how the deficit is tackled. Fed Chairman Paul Volcker has made clear on numerous occasions that a realistic move to cut the deficit would make it simpler for the central bank to relax its tight monetary grip of the past several years.