Can this be a problem for us later?

Yes, it could be.

We are not looking to tradmark/copyright the name.

You cannot copyright the name anyway; you trademark names. Not attempting to register the trademark may expose you to more litigation. So you might want to consider it.

And there will be no money to sue...

You don't need to have money to get sued. Somebody may only want you to stop using the name they have trademarked themselves.

I just don't want to get an angry letter demanding we change the name of the game after it is released...

Unfortunately, somebody else got there first and registered that trademark. Now, fortunately, trademarks are not universal: the same mark can be used by different people/organizations in different industries. Movies and games are different, but they could both be broadly considered part of the entertainment issue, so there's not really a clear-cut answer for whether or not your name infringes on the movie's trademark. So it's very possible the holders of the trademark would balk at your use and attempt to stop you. It really depends on them.

You should probably consult a lawyer about your options.

I don't think it's logical for me to spend 100's of $$$ on a lawyer. This game is a hobby, with 0 expectations of making money.

It doesn't have to cost "hundreds of dollars." Many lawyers will consult with you for very reasonable prices.

It costs you way more if you are taken to court. This is the cost of doing business. You don't have to pay it, but you take a risk in doing so. You may lose all of your hard work. Talk to a lawyer. They'll tell you what they'll charge you up front.

Does it matter that we want to call our game "Time Rider" while the movie is called "Timerider: The Adventure of Lyle Swann" ?

Yes. The fact that it's not the exactly same title is a point in your favor; however trademark law still often comes down to "would a consumer confuse your product for their product" queries, and so similarity is still a factor.

Why "rider" anyway? In typical USA conversation, someone "riding" a car is merely a passenger, not an active participant - otherwise, they'd be "driving" the car.

Why not TimeDrive, TimeSteer, Time Tread, ChronoDrive, DriveTime, or ClockDrive, or any of a few hundred other options? Chrono Km/h?

I understand if you have such an awesome name that you really want to take the risk, but Time Rider sounds rather generic and lacking in creativity, as far as names go.

Time Treader,

With that said, you are making a game. If the game is not based on the movie and it is more that they have similar titles than you should be fine for a hobby project.

Just a small nitpick: It doesn't matter what type of project it is - commercial, hobby, etc. The same laws apply irregardless.

Since the titles are not exactly the same, the medias are different and there is little chance of confusion. You SHOULD probably be good. One thing to note is since it is from the 1980's there is a chance the trademark has expired. A trademark must be in active commerce for it to remain valid. (there is some small leway on that but it is usually only for a short hiatus or you are preparing to bring it to market and paid the trademark office and reserved it) Since it is a B rate movie it may have been dropped from being sold. Check here: http://tmsearch.uspto.gov/bin/gate.exe?f=tess&state=4802:v4au11.1.1

I think you should be fine (you should always consult a licensed lawyer if you wan to be sure.) But becareful of copyright law. That does not expired just because of non-use. So if your game is too similar to the movie you might get a take down notice on that front.